Ceiling panel structure for a ceiling-mounted air-conditioning apparatus or the like

ABSTRACT

A ceiling panel structure ( 10; 310 ) is mounted on a ceiling surface ( 201 ) at a downstream of an air-outlet ( 211 ) of a ceiling-mounted air-conditioning apparatus (indoor unit) ( 200 ) having an air-inlet ( 210 ) at a central portion and the conditioning air-outlet ( 211 ) at a peripheral portion to minimize the smudging of the ceiling surface and is applicable even to the pre-mounted or existing air-conditioning apparatus. The ceiling panel structure ( 10; 310 ) is adapted to be mounted on the ceiling surface ( 201 ) at an outside of the air-conditioning apparatus ( 200 ) and has a deflection induction portion ( 47; 347 ) substantially rigid against the airflow to deflect a part (S 1 , S 2 ) of the conditioning air, having been blown out through the air-outlet ( 211 ) of the air-conditioning apparatus ( 200 ), back to the room air-inlet ( 210 ). The ceiling panel structure ( 10; 310 ) comprises, typically, a base member ( 20; 320 ) mounted on the ceiling ( 201 ) and a cover member ( 40; 340 ) attached to the base member ( 20; 320 ) and having portions such as the deflection induction portion ( 47; 347 ).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to an art for reducing smudging of aceiling by a conditioning air blown out through an outlet of aceiling-mounted air-conditioning apparatus (referred to hereinafter alsoas “ceiling-mounted air-conditioner”) or the like.

[0003] 2. Description of the Related Arts

[0004] An air-conditioning system essentially includes a pair of heatexchangers through which heating/cooling medium is circulated. The airis warmed or heated/cooled when passing through one of the heatexchanger while the medium having been cooled/heated uponwarming/cooling the air in said one heat exchanger is heated/cooled atthe other heat exchanger. In the air-conditioning system where the pairof heat exchangers are made of separate units, the unit including saidone heat exchanger is usually called “indoor unit” or “package typeair-conditioner” while the other is called “outdoor unit”. Theceiling-mounted air-conditioning apparatus where apparatus is mounted orinstalled or almost embedded in the ceiling corresponds to the indoorunit (see for example U.S. Pat. No. 5,595,068). More specifically, theceiling-mounted air-conditioner has a room air-inlet at a centralportion of a bottom thereof and a conditioning air-outlet at aperipheral portion of the bottom thereof, so that the air-conditionersucks or introduces the room air from the room air-inlet at the centralportion of the bottom portion thereof and, after having warmed or cooledthe introduced room air by the heat exchanger thereof, discharges orblows out the conditioning air from the air-outlet at the peripheralportion of the bottom portion.

[0005] The conditioning air is blown out in a direction generally alonga ceiling surface so that the conditioning air can spread over a wideregion in the room and, therefore, the air inherently tends to flowalong the ceiling surface. Accordingly, the conditioning air smudges anarea of the ceiling surface near the air-outlet due to the contaminationof the conditioning air itself or the contamination of the room airwhich is entangled in a rapid flow of air blown out through theair-outlet. When the air-conditioning apparatus has been used for a longperiod of time, the smudged ceiling surface becomes too unsightly to beneglected.

[0006] It is proposed, for solving above-mentioned problems, to adjustan inclination of a wind direction plate, which is disposed near theair-outlet within an air discharge passage, in response to a degree ofcontamination of the room air and a selected air-conditioning state,i.e., cooling or warming, so as to change a direction of conditioningairflow from the air-outlet (refer for example to Japanese PatentApplication Publication (i.e., Laid-Open) No. 8-100942 (100942/96), orto change an air discharge direction and/or size of an opening near eachof longitudinal ends of an air-outlet, where the discharged air tends toflow along the ceiling surface (refer for example to Japanese PatentApplication Publication Nos. 7-324802 (324802/95), 8-313042 (313042/96)and 9-222237 (222237/97).

[0007] These proposals are directed to regulate or control theconditioning airflow directly at the air-outlet formed or defined as apart of an outer casing or frame of the air-conditioning apparatus,sizes or dimensions of which are practically limited. However, suchdirect control of the overall airflow at the air-outlet where the flowspeed or flow rate is high encounters various disadvantages, i.e., whenthe airflow is controlled not to be directed to the ceiling surface,there is a possibility that intended effects cannot be obtained becauseof the possibility that the conditioning air cannot be spread fully inthe room, and also that the adjustment conditions should be changed whenthe flow rate changes.

[0008] Japanese Patent Application Publication No. 8-94160 (94160/96)discloses to have a step or projection, on a cover plate constituting anouter frame of the air-conditioning apparatus, which acts to deflect theconditioning air, having been blown out through the air-outlet of theair-conditioning apparatus, in a direction away from the ceilingsurface. A Microfilm of Japanese Utility Model Application No. 61-8595(8595/86) corresponding to Japanese Utility Model ApplicationPublication No. 62-120151 (120151/87) discloses to have a blow-out guideof “L”-shaped cross-section which provides similar function. However,there is a possibility that these arts also encounter the similarproblems.

[0009] In addition, the above-mentioned prior arts directed tomodification of a body of the air-conditioning apparatus cannot solvethe problem of the contamination or smudging of the ceiling surfacewhere the ceiling-mounted air-conditioning apparatus has been alreadymounted or installed.

[0010] Another attempt has been made domestically inside of Japan, i.e.the attempt described now in this paragraph is not a prior art except ina country where novelty- and/or obviousness-related provisions/provisiondefine/defines that publicly accessible use of the structure even in theother country or countries may also constitute the prior art. In thisattempt, a transparent plastic film or sheet having been bent in anobtuse angle was attached an area of the ceiling surface where smudgingis likely to be produced. However, when the flow rate of the blown-outair is low, there is a possibility that the air flows over the obtuselybent wall of the plastic film to smudge an area of the ceiling surfaceoutside of the attached plastic film. On the other hand, when the flowrate of the blown-out air is high, an obtusely inclined and dependentdeflection portion of “L”-shaped cross-section is pressed by the airflowto be deformed away from the airflow.

[0011] In the meantime, It is also proposed to form a peripheral portionof an air-conditioning duct opened in the ceiling with an arcuatelycurved portion so as to reduce contamination or smudging of the ceilingsurface (Japanese Utility Model Application Publication No. 7-12847(12847/95)). However, this proposal also involves similar problems asthe above-mentioned proposed ceiling-mounted air-conditioningapparatuses. In addition, behavior of conditioning airflow having beenblown out through the air-outlet in the air-conditioning duct issomewhat different from that of the air-conditioning apparatus havingthe air-inlet at the central portion and the air-outlet at theperipheral portion, because the air-conditioning duct does not have theair-inlet in the opening but the whole opening serves as the air-outlet.

SUMMARY OF THE INVENION

[0012] The invention has been made in view of the foregoing, and oneobject of the invention is to provide a ceiling panel structure capableof being applied also to an existing, i.e., pre-installed,ceiling-mounted air-conditioning apparatus which has been alreadyinstalled or mounted to the ceiling and of minimizing smudging orcontamination of the ceiling surface around the air-conditioningapparatus.

[0013] Another object of the invention is to provide a ceiling panelstructure facilitating mountability thereof even in a case where theceiling surface is not flat but undulated.

[0014] Still another object of the invention is to provide a ceilingpanel structure including a base member or structure and a cover memberor structure, in which engagement/disengagement of the cover member orstructure with/from the base member or structure can be facilitated,i.e., carried out easily.

[0015] According to the invention, the above-mentioned one object can beaccomplished by a ceiling panel structure adapted to be mounted to aceiling at a downstream of a conditioning air-outlet of aceiling-mounted air-conditioning apparatus, having a room air-inlet at acentral portion thereof and the air-outlet at a peripheral portionthereof, said ceiling panel structure being adapted to be mounted to theceiling at an outside of the air-conditioning apparatus, and comprisinga deflection induction portion which is substantially rigid against anairflow to deflect a part of the conditioning air, having been blown outthrough the outlet of the air-conditioning apparatus, back to the roomair-inlet.

[0016] Because the ceiling panel structure of the invention comprises,“a deflection induction portion which is substantially rigid against anairflow to deflect a part of the conditioning air, having been blown outthrough the outlet of the air-conditioning apparatus, back to the roomair-inlet”, only by mounting the ceiling panel structure to apredetermined position of the ceiling, the ceiling panel structure candeflect, by means of the deflection induction portion thereof, theairflow having been blown out through the air-outlet of theair-conditioning apparatus back to the room air-inlet, thereby enablingto minimize the conditioning airflow to blow against or impinge on theceiling surface and to spread therealong and therefore enabling tominimize the ceiling surface to be smudged by fine solid and/or liquidparticles contained in the conditioning air. In addition, because thedeflection induction portion is substantially rigid against the airflow,the deflection induction portion can deflect the airflow, i.e., changethe direction of airflow into predetermined directions even in a casewhere the air flows relatively rapidly. Further, the ceiling panelstructure is situated in a spatial region, near the ceiling surface andmore or less remote from the air-outlet of the air-conditioningapparatus, which is open to a room or indoor space, the airflow canspread more or less before impinging on the deflection induction portionand can be directed to spread downwards upon impinging on the deflectioninduction portion, so that the conditioning airflow can be deflectedappropriately upon impinging on the deflection induction portion.Although the deflection induction portion is typically constituted by adeflection guide part having a concavely curved guide surface to deflectthe airflow therealong, the detailed or concrete configuration or shapethereof may be of any form so long as the direction of airflow can bechanged significantly. Meanwhile, it is typically preferred to reducebeforehand the flow rate and the wind pressure or dynamic pressurethereof to be described later so as to change significantly thedirection of airflow by the deflection induction portion. Furthermore,because the ceiling panel structure is mounted to the ceiling, at thedownstream of the air-outlet, around or outside the air-conditioningapparatus, the air-conditioning apparatus may have been alreadyinstalled in the ceiling. When mounted around the air-conditioningapparatus having been already installed in the ceiling, the ceilingpanel structure of the invention can not only prevent the furtherprogress of the smudging of the ceiling but also serve for hiding thesmudge of the ceiling by covering a part of the smudged ceiling.

[0017] The ceiling panel structure and/or element(s) thereof is mountedor attached to the “lower” face of the ceiling, which may be expressedhereinafter as being mounted “on” the ceiling surface or “on” theceiling, although, strictly expressing, the ceiling panel structure orthe like is mounted “beneath” the ceiling surface or ceiling.

[0018] Considering to facilitate the mounting work of the ceiling panelstructure on the ceiling surface, the ceiling panel structure accordingto a preferred embodiment of the invention typically comprises at leastone base member adapted to be mounted to a ceiling at the downstream ofthe air-conditioning apparatus and having an engaging portion at a sidethereof opposite to a side faced to the ceiling; and at least one covermember engaged at an engaged portion thereof with the engaging portionof said at least one base member to be fixed thereto, said at least onecover member having the deflection induction portion.

[0019] In the ceiling panel structure of the preferred embodiment,because “the cover member has the deflection induction portion which issubstantially rigid against an airflow to deflect a part of theconditioning air, having been blown out through the air-outlet of theair-conditioning apparatus, back to the room air-inlet”, only byengaging the cover member with the base member, having been attached tothe predetermined position of the ceiling, to be fixed thereto, theceiling panel structure can deflect, by means of the deflectioninduction portion of the cover member, a part of the airflow having beenblown out through the outlet of the air-conditioning apparatus back tothe room air-inlet, thereby enabling to minimize the conditioningairflow to impinge on the ceiling surface and to minimize the airflow tospread along the ceiling surface. In addition, because the deflectioninduction portion of the cover member is substantially rigid against theairflow, the deflection induction portion can deflect the airflow, i.e.,change the direction of airflow into predetermined directions even in acase where the air flows relatively rapidly. Further, the cover memberis situated in the spatial region, near the ceiling surface and more orless remote from the air-outlet of the air-conditioning apparatus, whichis opened to a room or indoor space, the airflow tends to be deflectedappropriately upon impinging on the deflection induction portion.

[0020] In addition, because the ceiling panel structure of theembodiment comprises “at least one base member to be mounted to theceiling at the downstream of the air-conditioning apparatus and havingan engaging portion at a side opposite to the ceiling, and at least onecover member engaged at an engaged portion thereof with the engagingportion of said at least one base member to be fixed thereto”, the covermember can be easily fixed to the ceiling surface at the predeterminedposition.

[0021] More specifically, the ceiling panel structure having aconfiguration for adjusting the conditioning airflow has necessarily aconsiderable thickness. If such a thick ceiling panel structure isintended to be fixed directly to the ceiling surface without affectingan appearance thereof, it will become necessary to have a configurationfor preventing heads of fastening screws or the like from being exposed,which would in turn make it difficult or hard to carry out the mountingwork thereof to be done facing upward toward the ceiling surface from alower position, or which would require plural persons or workmen tocarry out even a simple mounting work. In contrast to these situations,in the above-mentioned embodiment of ceiling panel structure, becausethe engaged portion of the cover member can be essentially formed at aside faced to the base member to be engaged with the engaging portionthereof, the mounting work of the cover member can be carried out withease even by the minimum number of person(s), e.g., by the singleworkman.

[0022] Further, because the base member is provided separately from thecover member in the ceiling panel structure of the embodiment, the basemember can be configured to facilitate the mounting work thereof byscrews etc. on the ceiling surface without consideration of appearancethereof, and to have the engaging portion for facilitating theengagement thereof with the cover member. As a result, the mounting workof the base member on the ceiling is facilitated and can be performedeven by the minimum person(s), e.g., by one person. Moreover, theengaging portion of the base member can be covered to be hidden by thecover member, the engaged portion of the cover member can be designed tohave a configuration or structure as desired in view of ease of mountingand strength of engagement and fixation, and therefore theengagement/fixation of the cover member with/to the base member can becarried out easily. Accordingly, both mounting work of the base memberto the ceiling surface and engagement/fixation of the cover memberwith/to the base member can be performed by the minimum person(s), e.g.,by one person, which results in that the whole mounting work of theceiling panel structure on the ceiling surface can be performed by theminimum number of person(s), e.g., by one person. Each of the cover andbase members may be formed by a single or integral member or bycombination of plural members or parts.

[0023] The ceiling-mounted air-conditioning apparatus may have any outershape or any two dimensional shape, such as a rectangular (square orquadrilateral) or circular shape or other shape, in which a lower end ofthe apparatus extends or spreads along the ceiling surface in a statewhere almost all of the apparatus is embedded in the ceiling, so long asthe apparatus has the room air-inlet at the central portion thereof andthe conditioning air-outlet at the peripheral portion thereof. As amatter of course, although the air-conditioning apparatus has more orless three dimensional shape protruding downward from the ceilingsurface, the three dimensional shape may be of may form so long as theapparatus has the room air-inlet at the exposed central bottom partthereof and the conditioning air-outlet at the exposed peripheral bottompart thereof.

[0024] The conditioning air-outlet may be provided at only a part of theperipheral portion or part of the apparatus or over substantially thewhole periphery thereof, so long as the air-outlet is provided at theperiphery and is configured or adapted to blow out the conditioning airmore or less outwards. For example, in a case where the two dimensionalshape or configuration of the air-conditioning apparatus on the ceilingsurface, i.e., shape in plan view (strictly, bottom view), isrectangular, the air-outlet may be formed along only one side of thefour sides of the rectangle or along two parallel sides thereof or alongall of the four sides thereof. The air-outlet may be formed at thecorner.

[0025] The ceiling panel structure according to an embodiment of theinvention typically comprises the cover member(s) each having thedeflection induction portion to deflect the flow of the conditioning airblowing out of the associated one of the air-outlet(s). Therefore, in acase of one linearly extending air-outlet, the cover member(s) typicallycomprises a single linear cover member (as a matter of course, thesingle cover member may be formed by combination of plural parts).However, if desired, the cover member(s) may further comprise, at thelongitudinal end(s) of the linear cover member, a corner cover member(s)curved at the corner(s), or the cover member may be configured like apicture frame in the form of a rectangular or four-sided closed loop tosurround all the periphery of the air-conditioning apparatus.

[0026] The base member has typically a two-dimensional shape orconfiguration similar to that of the cover member to be engaged by thecover member to be fixed thereto. Thus, when the cover member is alinear cover member, the base member is typically a linear base member,while the base member is typically a corner base member curved at thecorner when the cover member is a corner cover member curved at thecorner. However, the base member may have a two dimensional shapedifferent from that of the cover member, so long as the base member canengage the cover member to be fixed thereto. For example, when the covermember is a linear cover member, requirement in the base member(s) is toengage at least a part of the cover member near either longitudinal endthereof to support it. Thus, both ends of the linear cover member may besupported by the associated corner base members situated at theassociated corners.

[0027] Typically, the surface of the cover member has a configuration,for the purpose of adjusting the conditioning airflow, to deflect theairflow (i.e., to change the direction of airflow), to provide aresistance against the airflow (i.e., to serve as flow-resistanceagainst the airflow thereby reducing the wind pressure and flow rate ofthe air) and/or to guide the airflow (i.e., to regulate the direction ofairflow without substantially preventing the flow of air, while changingor not changing the direction of the airflow). In a case where the covermember covers the base member substantially completely, only the surfaceof the cover member performs these functions. However, a part of thebase member may be exposed at the ceiling surface without being coveredby the cover member. Such being the case, surface configuration for thedeflection, flow-resistance (reduction in flow rate) and/or flow-guide,to adjust the conditioning airflow may be partially provided by the basemember. Even in the circumstances, the cover member serves not only foradjusting the conditioning airflow at the deflection induction portionthereof and for covering to hide a mounting structure portion of thebase member to the ceiling surface, but also for covering to hide theengagement portions of the base member and cover member. The inductionor guide portion having a flow-deflection function has more or less theflow-resistant function also.

[0028] Thus, in a typical ceiling panel structure according to anembodiment of the invention, said at least one base member comprises alinear base member capable of being mounted at one principal facethereof to a surface of the ceiling to extend along at least one linearside edge of the air-conditioning apparatus, the linear base memberhaving an adjustable length and/or width, and said at least one covermember comprises a linear cover member engaged with the linear basemember and having an adjustable length. In addition, the linear basemember comprises, a conditioning airflow guide surface at one widthwiseend portion of a principal face opposite to said one principal facegenerally parallel to said one principal face, said one widthwise endportion being closer, than another widthwise end, to the side edge ofthe air-conditioning apparatus where the air-outlet is provided; and theengaging portion at a position more remote, than the guide surface, inthe widthwise direction from the side edge of the air-conditioningapparatus. Moreover, the linear cover member comprises the deflectioninduction portion for deflecting a part of the conditioning air, flowingalong the guide surface of the linear base member, back to the roomair-inlet.

[0029] In addition, in one typical ceiling panel structure according toan embodiment of the invention, the linear base member further comprisesa flow-resistant projection portion, at a widthwise outer end of theguide surface, engaged with a widthwise inner end of the linear covermember and serving as a resistance against the airflow for reducing aflow rate of the conditioning air having spread along the guide surface.

[0030] Further, in one typical ceiling panel structure according to anembodiment of the invention, the cover member comprises a flow-resistantprojection portion, at an upstream of the deflection induction portion,which serves as a resistance against the airflow for reducing a flowrate of the conditioning air flowing along the surface of the covermember. There may be a plurality of such flow-resistant projections.Typically, the flow-resistant projection of the cover member is adaptedto have a higher flow-resisting function than that of the base member.However, the relationship therebetween may be reversed.

[0031] In any case, the appropriate reduction in the wind pressure orflow rate of the conditioning air before flowing into the deflectioninduction portion allows the airflow impinging on the deflectioninduction portion to tend to flow along the guide face of the deflectioninduction portion.

[0032] The ceiling panel structure is formed to have a shape and sizesaccording to an outer shape and dimensions (sizes) of theair-conditioning apparatus mounted in the ceiling surface. Therefore,the base and cover members constituting the ceiling panel structure areformed to be length-adjustable. The length adjustment is typicallycarried out by cutting by means of the saw or the like the base andcover members, each having a constant shape in a cross-sectionperpendicular to the longitudinal direction thereof, at the mountingwork or job site by the workman. Therefore, the base and cover membersconstituting the ceiling panel structure are typically made of plasticmaterial and are produced by extrusion molding. The plastic material maybe for example vinyl chloride resin. However, other plastic material maybe used to minimize the environmental pollution. The material of themembers may, however, be others such as metal, wood or compositematerial of metal and plastics so long as the member can be cut with asaw etc. at the mounting job site by the workman.

[0033] The ceiling panel structure is mounted around theair-conditioning apparatus according to an unoccupied area therearoundof the ceiling surface where the apparatus is mounted, typically in amanner to avoid obstacle(s), such as a power-supply line or electricwiring output and various sensors like a smoke sensor, which may happento be in or on the ceiling surface near the outer periphery of theair-conditioning apparatus. Therefore, in the ceiling panel structure,typically, the constituent base and cover members are also designedwidth-adjustable. In some case, a longitudinal side of theair-conditioning apparatus may be as long as 2 meters. Therefore, inorder to facilitate the width-adjustment over about a length of 2 metersalong the longitudinal direction thereof, the ceiling panel structurehas typically weakened parts extending in the longitudinal directionthereof to allow, if desired, a widthwise end part thereof to be removedby forming a cutting line therealong by means of a cutter knife or thelike so that the width thereof can be adjusted. Typically, each of theweakened parts comprises the a groove, extending in the longitudinaldirection. Such grooves are formed in a rear face, i.e. a side faced tothe ceiling, in view of appearance.

[0034] Therefore, in a typical ceiling panel structure according to anembodiment of the invention, said at least one base member comprises alinear base member capable of being mounted at one principal facethereof to a surface of the ceiling to extend along at least one linearside edge of the air-conditioning apparatus, the linear base memberhaving an adjustable length and/or width, and said at least one covermember comprises a linear cover member engaged with the linear basemember and having an adjustable length.

[0035] In this case, it is possible to mount the linear base memberavoiding the obstacle(s) near the air-conditioning apparatus byadjusting the width of the base member. In addition, it is possible toadjust the lengths of the linear base and cover members at the mountingjob site, according to the length of the air-outlet of theair-conditioning apparatus or a size of a side extending parallel withthe air-outlet of the apparatus, to mount or install the ceiling panelstructure.

[0036] In a typical ceiling panel structure according to an embodimentof the invention, the base member includes a corner base member capableof being mounted at one principal face thereof to the ceiling surfaceadjacent to a longitudinal end of the linear base member at an outsideof a corner portion of the air-conditioning apparatus, and wherein thecover member includes a corner cover member engaged with the corner basemember adjacent to a longitudinal end of the linear cover member.

[0037] In this case, for example, the ceiling panel structure may have,in plan view, a generally rectangular shape or the like to surroundtypically all the periphery of the air-conditioning apparatus or to besituated at least around two sides thereof.

[0038] In a typical ceiling panel structure according to an embodimentof the invention, the base member includes a corner base member capableof being mounted to a surface of the ceiling at an outside of a cornerportion of the air-conditioning apparatus, and wherein the cover memberincludes a linear cover member engaged with the corner base member ateither longitudinal end thereof and having an adjustable length andwidth; and a corner cover member engaged with the corner base memberadjacent to the longitudinal end of the linear cover member. In thiscase, the base member is minimized while facilitating the mounting.However, in a case where the air-conditioning apparatus is of largedimension or size and length(s) of the linear base member(s) is long,another or separate base member may be disposed at a rear side, of anintermediate position of the linear cover member, i.e. between theceiling surface and the cover member, to support the linear cover memberfirmly.

[0039] A typical ceiling panel structure according to an embodiment ofthe invention is adapted to be mounted to a ceiling at a downstream of aconditioning air-outlet of a ceiling-mounted air-conditioning apparatus,having a room air-inlet at a central portion thereof and the air-outletat a peripheral portion thereof, said ceiling panel structure comprisinglinear panel structures and corner panel structures, wherein each of thelinear panel structures comprises a base member capable of being mountedto a surface of the ceiling at one principal face thereof to extendalong an associated linear side edge of the air-conditioning apparatus,a length and width of the base member in an extending direction thereofbeing adjustable, the base member having an engaging portion at aprincipal face thereof opposite to said one principal face, a covermember of an adjustable length and width adapted to be engaged with theengaging portion of the associated base member at an engaged portionthereof to be fixed thereto, the cover member having a deflectioninduction portion which is substantially rigid against an airflow todeflect a part of the conditioning air, having been blown out throughthe outlet of the air-conditioning apparatus, back to the roomair-inlet, and each of the corner panel structure is adapted to bepositioned between adjacent ends of the associated linear panelstructures to be engaged with the adjacent ends.

[0040] So long as the smudge on the ceiling surface near the air-outletof the ceiling-mounted air-conditioning apparatus having been alreadyinstalled or mounted can be covered to be hidden, at least a part or allof the base and/or cover members may be transparent or semi-transparent.However, in order to ensure to cover and hide the smudge on the ceilingsurface near the air-outlet of the ceiling-mounted air-conditioningapparatus having been already installed, it is preferred that the baseand cover members are typically made of substantially opaque material,while at least a part of the members may be made of transparent orsemi-transparent material in a case where the ceiling surface is notsmudged yet or where the air-conditioning apparatus is mounted in theceiling surface for the first time.

[0041] According to one aspect of the invention, the above-mentionedanother object of the invention can be attained by a ceiling panelstructure adapted to be mounted to a ceiling at a downstream of aconditioning air-outlet of a ceiling-mounted air-conditioning apparatus,having a room air-inlet at a central portion thereof and the air-outletat a peripheral portion thereof, the ceiling panel structure including adeflection induction portion which is substantially rigid against anairflow to deflect the conditioning air, having been blown out throughthe outlet of the air-conditioning apparatus, in a direction away fromthe ceiling, the ceiling panel structure comprising a base structureadapted to be mounted to a ceiling at an outside of the air-conditioningapparatus and having an engaging portion at a side opposite to a sidefaced to the ceiling, the base structure including a linear base memberadapted to be mounted to a surface of the ceiling at one principal facethereof to extend along a side edge of the air-conditioning apparatus;and a cover structure engaged at an engaged portion thereof with theengaging portion of the base structure to be fixed thereto, the coverstructure including a linear cover member adapted to be engaged with thelinear base member and having the deflection induction portion; whereinthe engaging portion of the linear base member comprises a pair ofengaging recesses spaced from each other in a widthwise directionthereof and opened at opposite sides to be faced away from each other,one of the recesses having side walls, one of the side walls situatedcloser to the surface of the ceiling than another of the side wallshaving an inclined face inclined to be closer to the surface of theceiling as departing more remote from another of the recesses, andwherein the engaged portion of the linear cover member comprises a pairof engaged projections, to be engaged with the pair of engaging recessesof the linear base member, at regions spaced from each other in awidthwise direction of the linear cover member, the pair of the engagedprojections being situated at sides faced to each other and beingcapable of being displaced resiliently toward/from each other, one ofthe projections having a guide part movable along the inclined face ofthe side wall, closer to the surface of the ceiling, of said one recess.

[0042] Because the ceiling panel structure according to said one aspectof the invention is adapted to be mounted or installed to the ceilingoutside the air-conditioning apparatus and includes “a deflectioninduction portion substantially rigid against the airflow for deflectingthe airflow, having been blown out through the air-outlet of theair-conditioning apparatus, in a direction away from the ceiling(surface)”, by mounting the ceiling panel structure at a predeterminedposition of the ceiling outside the apparatus, it is possible to deflectby the deflection induction portion the conditioning airflow, havingbeen blown out through the air-outlet of the air-conditioning apparatus,in the direction away from the ceiling, to minimize the conditioningairflow out of the air-outlet to blow against or impinge on the ceilingand/or to spread along the ceiling surface, thereby minimizing thesmudging of the ceiling surface by fine particles or the like such assolid or liquid particles contained in the conditioning airflow. Inaddition, because the deflection induction portion is substantiallyrigid against the airflow, the deflection induction portion can deflectthe airflow (change the direction of the airflow) in a predetermineddirection(s) even when the airflow is relatively strong or rapid.Further, because the ceiling panel structure is situated in a spatialregion, near the ceiling surface and more or less remote from theair-outlet of the air-conditioning apparatus, which is opened to a roomor indoor space, the airflow more or less spreads before impinging onthe deflection induction portion and can be directed to spread downwardsupon impinging on the deflection induction portion, so that theconditioning airflow having impinged on the deflection induction portioncan be deflected appropriately.

[0043] Further, because the ceiling panel structure of theabove-mentioned one aspect comprises “a base structure adapted to bemounted to a ceiling at an outside of the air-conditioning apparatus andhaving an engaging portion at a side opposite to the ceiling, the basestructure including a linear base member adapted to be mounted on theceiling surface at one principal face thereof to extend along a sideedge of the air-conditioning apparatus; and a cover structure engaged atan engaged portion thereof with the engaging portion of the basestructure to be fixed thereto, the cover structure including a linearcover member adapted to be engaged with the linear base member”, themounting or installation of the ceiling panel structure can be carriedout with ease by mounting the base structure on the ceiling surface withfixing means such as screws, by laying the cover structure on(beneath)the base structure to cover mounting part(s) of the fixing or mountingmeans, and by engaging the engaged portion of the cover structure withthe engaging portion of the base structure. The base structure typicallycomprises the linear base member and a corner base member, while thecover structure typically comprises the linear cover member and a cornercover member. However, the base structure may be constituted by onelinear base member and the cover structure may be constituted by onelinear cover member.

[0044] Because the linear base member is provided separately from thelinear cover member also in the ceiling panel structure of theembodiment according to said one aspect, the linear base member can beconfigured to facilitate the mounting work thereof by screws etc. on theceiling surface without consideration of appearance a part thereof to becovered by the linear cover member, and to have the engaging portion forfacilitating the engagement thereof with the linear cover member. As aresult, the mounting work of the linear base member on the ceiling isfacilitated and can be performed even by the minimum person(s), e.g., byone person. Moreover, the engaging portion of the linear base member canbe covered to be hidden substantially by the linear cover member, theengaging portion of the linear base member and the engaged portion ofthe linear cover member can be designed to have configurations orstructures as desired in view of easy and firm engagement andfixation/easy disengagement, and therefore the engagement andfixation/disengagement of the linear cover member with and to/from thelinear base member can be carried out easily. Accordingly, both mountingwork of the linear base member to the ceiling surface andengagement/fixation of the linear cover member with/to the linear basemember can be performed by the minimum person(s), e.g., by one person,which results in that the whole mounting work of the ceiling panelstructure on the ceiling surface can be performed by the minimum numberof person(s), e.g., by one person. Each of the linear cover and basemembers may be formed by a single or integral member or by combinationof plural members or parts.

[0045] In addition, in the ceiling panel structure of said one aspectaccording to the invention, because “the linear cover member comprisesthe deflection induction portion which is substantially rigid against anair flow to deflect the conditioning air, having been blown out throughthe outlet of the air-conditioning apparatus, in a direction away fromthe ceiling”, the engaging portion of the linear base member and theengaged portion of the linear cover member can be arranged with easewithin a region defined by a thickness and width, of the linear covermember, required for providing an airflow-adjustment structure such asthe deflection induction portion for adjusting the conditioning airflow,thereby enabling to provide the engaging portion and engaged portion inthe form appropriate for the mounting work.

[0046] Herein, i.e., in the specification, as to the linear covermember, “adapted to be mounted on the ceiling surface at one principalface” typically means that the member is mounted on the ceiling surfacein a state said one principal face contacts directly with the ceilingsurface. However, if desired, the linear base member may be mounted onthe ceiling surface in a state where a projection (leg) or projections(legs) projecting from said one principal face toward the ceilingsurface abuts against the ceiling surface. In addition, as to the linearbase member, “to extend along the side edge of the air-conditioningapparatus” means typically that the air-conditioning apparatus has alinear side edge and the linear base member extends parallel with thelinear side edge of the apparatus. However, if desired, the linear basemember may not be parallel. Further, in a case where the side edge ofthe air-conditioning apparatus is not linear, it is sufficient that thelinear base member extends in a direction generally identical orparallel with an average extending direction of the side edge. Moreover,as to the engaging portion of the linear base member, “a side oppositeto a side faced to the ceiling” or “a side opposite to the ceiling” isintended to includes a portion or part protruding in a desired directionfrom the side opposite to (the side faced to) the ceiling, that is, theside is not limited to a face parallel to the ceiling surface butincludes a face not parallel with the ceiling surface.

[0047] Typically, the surface of the linear cover member has aconfiguration, for the purpose of adjusting the conditioning airflow, todeflect the airflow (i.e., to change the direction of airflow), toprovide a resistance against the airflow (i.e., to serve asflow-resistance against the airflow thereby reducing the wind pressureand flow rate of the air) and/or to guide the airflow (i.e., to regulatethe direction of airflow without substantially preventing the flow ofair, while changing or not changing the direction of the airflow). In acase where the linear cover member covers the linear base membersubstantially completely, only the surface of the linear cover memberperforms these functions. However, a part of the linear base member maybe exposed at the ceiling surface without being covered by the linearcover member. Such being the case, surface configuration for thedeflection, flow-resistance (reduction in flow rate) and/or flow-guide,to adjust the conditioning airflow may be partially provided by the basemember. Even in the circumstances, the linear cover member serves notonly for adjusting the conditioning airflow at the deflection inductionportion thereof and for covering to hide a mounting structure portion ofthe base member to the ceiling surface, but also for covering to hidethe engagement portions of the linear base member and linear covermember. The induction or guide portion having a flow-deflection functionhas more or less the flow-resistant function also.

[0048] In addition, in the ceiling panel structure according to said oneaspect of the invention, because “the engaging portion of the linearbase member comprises a pair of engaging recesses spaced from each otherin a widthwise direction thereof and opened at opposite sides to befaced away from each other, and the engaged portion of the linear covermember comprises a pair of engaged projections, to be engaged with thepair of engaging recesses of the linear base member, at regions spacedfrom each other in a widthwise direction of the linear cover member, thepair of the engaged projections being situated at sides faced to eachother”, the pair of engaging portions of the linear base member as wellas the pair of engaged portions of the linear cover member to be engagedtherewith can be covered behind the linear cover member, and theengagement/disengagement of the engaged portions of the linear covermember with/from the engaging portions of the linear base member can beperformed respectively by engaging/disengaging, with/from said one ofthe pair of engaging recesses, the associated one of the pair of engagedprojections of the linear cover member, in a state where said another ofthe pair of engaging recesses of the linear base member engages theassociated one of the engaged projections of the linear cover member. Inaddition, because the pair of the engaging recesses of the linear basemember are opened to sides or senses of direction widthwise opposite toeach other, both of side walls or wall portions defining each recess canextend along the longitudinal direction of the linear base membergenerally in parallel with the ceiling surface, the side walls can bedeformed to be undulated in the longitudinal direction according to anundulation of the ceiling surface. Further, because the pair of engagedprojections of the linear cover member protrude in widthwise oppositesenses of direction to each other, each projecting rib defined by theengaged projection also extends along the longitudinal direction of thelinear cover member generally in parallel with the ceiling surface, sothat the ribs can be deformed with ease to be undulated relativelyfollowing to the undulation of the ceiling surface. Therefore, theundulation of the ceiling surface can be absorbed or compensatedrelatively with ease by the deformation, of the linear base and covermembers, corresponding thereto. That is, even if the linear base membermay be undulated to some extent according to the undulation of theceiling surface upon mounting thereof on the ceiling, into another ofthe pair of engaging recesses of the linear base member at a sideopposite to said one engaging recesses, the associated engagedprojection of the linear cover member can be fit in by force. In thiscase, in order that the insertion, into said another engaging recess, ofthe corresponding engaged projection can be induced or guided, it ispreferred that one of the side walls of said another engaging recess hasa guide face for guiding the insertion of the corresponding engagedprojection, that the engaged projection is tapered like a wedge, or thatthe engaging recess is opened to be wider as approaching closer to anopen end thereof.

[0049] In this case, preferably, the linear cover member has, near saidanother engaged portion, a plate portion expanding generally in parallelwith the ceiling surface, which facilitate the bending deformation ofthe linear cover member in the longitudinal direction according to theundulation of the ceiling surface. The plate portion can serve as aguide face for the conditioning airflow.

[0050] In addition, in the ceiling panel structure of said one aspect,“one of the recesses having side walls, one of the side walls situatedcloser to the surface of the ceiling than another of the side wallshaving an inclined face inclined to be closer to the surface of theceiling as departing more remote from another of the recesses, and oneof the engaged projections of the linear cover member corresponding tosaid one engaging recess having a guide part movable along the inclinedface of the side wall, closer to the ceiling surface, of said onerecess”, even when the linear cover member is undulated in thelongitudinal direction thereof according to the undulation of theceiling surface in case of undulated ceiling surface, the undulation canbe absorbed or compensated by displacement of the guide part of theengaged projection of the linear cover member, in a directionapproaching to or away from the ceiling surface, with respect to theinclined face of the side wall, of said one engaging recess of thelinear base member, closer to the ceiling. Therefore, even when theceiling surface is undulated, it is possible to avoid that theengagement/disengagement of the linear cover member with/from the linearbase member becomes too hard to performed smoothly.

[0051] The side wall, of the pair of side walls defining said one recessportion of the linear base member, situated more remote from the ceilingmay be generally parallel with the ceiling surface, but is preferred tohave an inclined face at a side, opposite to the ceiling surface, whichapproaches to the ceiling as departing more remote from said anotherrecess, so as to facilitate the engagement of the engaged portion of thelinear cover member with the engaging portion of the linear base member.

[0052] Such being the case, only by pressing the linear cover memberagainst the linear base member while engaging, with said anotherengaging recess of the engaging portions of the linear base member, thecorresponding engaged projection of the linear cover member, it ispossible to move or displace the guide part of the engaged projectionportion along the inclined face (opposite to the ceiling surface) of theside wall (situated more remote from the ceiling surface) of theengaging projection of the linear base member until the engagedprojection is displaced over the end of the inclined face, and to engagethe guide part thereof with the inclined face of said one side wall ofthe linear cover member. Thereafter, only by releasing the exertion ofpressing force on the linear cover member as desired, the engagement ofthe linear cover member with the linear base member can be accomplished.In the explanation above, it is assumed that a side wall (of said oneengaging recess portion) closer to the ceiling surface extends andterminates at a position more remote, from another engaging recessportion, than that of the side wall situated more remote from theceiling surface.

[0053] Further, by pressing the linear cover member against the linearbase member while the pair of engaged projections of the linear covermember are engaged with the corresponding pair of engaging recesses ofthe linear base member, it is possible to displace the guide part of oneof the engaged projections along the inclined face of one of theengaging recesses in a sense of direction away from another of engagingrecesses to increase a distance between the pair of engaging projectionsof the linear cover member. Thus, as desired, the engagement of thelinear cover member with the linear base member can be released byutilizing a tool or the like.

[0054] Each of the pair of engaging recesses of the linear base membermay extend intermittently in the form of a line over substantially thewhole length along the extending direction of the linear base member.However, in order to release the engagement of the engaged projectionwith the engaging recess as if peeling off the engagement from onelongitudinal end, it is preferred that at least said one engaging recessof the pair of recesses and therefore the side walls thereof extendscontinuously in the longitudinal direction of the linear base member,that is, the recess is in the form of a groove extending along thelongitudinal direction of the linear base member. Similar requirement orargument applies also to the corresponding engaged projection. For thedisengagement or release of engagement, a distal end of an elongatedtool such as screw driver may be utilized. Instead, a tool, such as athick walled spatula, shaped in the form of “L” to avoid interferencewith the ceiling surface may be used, where one of a pair of arms orlegs of “L” serves as a handle and a wall part connecting the arms orlegs are curved smoothly.

[0055] The linear cover member has typically a generally U-shapedcross-section, one engaged projection, of said one pair of the engagedprojections, engaged with said one recess of the linear base member isformed at one of two legs of the “U”, and the deflection inductionportion is formed at another of the two legs. In this case, by pressingthe bottom of “U” of the linear cover member while another recess of thelinear base member engages the engaged projection of the linear covermember, the engaged projection at the distal end of said one leg of “U”is displaced along the inclined face, of either side wall of said oneengaging recess of the linear base member in a sense of direction awayfrom the distal end of another leg of “U” to separate the distal ends ofthe two legs of “U”. Thus, the “U-shaped” cross-sectional portion of thelinear cover member facilitates the deformation of the linear covermember for engagement/disengagement thereof with/from the linear basemember. A certain magnitude or length is required in the legs of “U” forthe deflection induction portion to perform the defection action.Therefore, the “U-shaped” cross-sectional portion ensures the height forthe deflection induction portion on one hand and facilitates theengagement/disengagement of the linear cover member on the other hand.

[0056] In the description above, said one recess is situated typicallymore remote from the air-outlet of the air-conditioning apparatus thananother of the pair of recesses. However, when the downward protrudinglength from the ceiling surface may be relatively long, said one recessmay be situated closer than another to the air-outlet of theair-conditioning apparatus.

[0057] In a ceiling panel structure according to an embodiment of saidone aspect of the invention, typically, the linear base member comprisesa conditioning airflow guide face at a widthwise end portion, adjacentto the side edge of the air-conditioning apparatus where the air-outletis provided, of a principal face opposite to said one principal facegenerally parallel to said one principal face; and said another engagingportion at a position more remote in the widthwise direction than theguide face from the edge of the air-conditioning apparatus, and whereinthe linear cover member comprises said another engaged portion, engagedwith said another engaging portion of the linear base member, at awidthwise inner end thereof, a part of said another engaged portionfaced to the air-outlet of the air-conditioning apparatus serves as aflow-resistant projection acting as a resistance against the airflow forreducing a flow rate of the conditioning airflow having flown along theguide face of the linear base member.

[0058] Such being the case, a surface part of the engaged projection ofthe linear cover member at an opposite side to a surface part for theengagement serves, as it is, as the flow-resistant projection portion.The linear cover member may also have, at a region downstream of theopposite surface of the engaged projection and upstream of thedeflection induction portion, another flow-resistant projection, whichserves as a resistance against the conditioning airflow flowing alongthe surface of the cover member to reduce the wind pressure and flowrate thereof. In this case, typically, the downstream flow-resistantprojection is designed to have a higher flow-resistance than theupstream flow-resistant projection. However, the relationshiptherebetween may be reversed. In any case, appropriate reduction in theflow rate of the conditioning air flowing into the deflection inductionportion facilitate the airflow impinging on or blowing against thedeflection induction portion to be directed to flow along the guide faceof the deflection induction portion.

[0059] The ceiling panel structure typically comprises the covermember(s) each having the deflection induction portion to deflect theflow of the conditioning air blowing out of the associated one of theair-outlet(s). Therefore, in a case of one linearly extendingair-outlet, the cover member(s) typically comprises a single linearcover member (as a matter of course, the single cover member may beformed by combination of plural parts). Such being the case, it ispreferred that an end cap is fitted to cover an end thereof. Morespecifically, such being the case, the ceiling panel structurepreferably further comprises at least one end cap to cover at least onelongitudinal end of each of the linear base structure (typicallycorresponds to the linear base member) and the linear cover structure(typically corresponds to the linear cover member) in a state where theengaging portion of the linear base member engages the engaged portionof the linear cover member. However, if desired, the cover member(s) mayfurther comprise, at the longitudinal end(s) of the linear cover member,a corner cover member(s) curved at the corner(s), or the cover membermay be configured like a picture frame in the form of a rectangular orfour-sided closed loop to surround all the periphery of theair-conditioning apparatus.

[0060] Therefore, in a typical ceiling panel structure according to anembodiment of said one aspect of the invention, the base structurecomprises a linear base member capable of being mounted at one principalface thereof on the lower face of the ceiling to extend along at leastone linear side edge of the air-conditioning apparatus and havingadjustable length and width, and the cover structure comprises a linearcover member engaged with the linear base member and having anadjustable length.

[0061] In a typical ceiling panel structure according to an embodimentof said one aspect of the invention, the base structure a corner basemember capable of being mounted at one principal face thereof to theceiling surface adjacent to a longitudinal end of the linear base memberat an outside of a corner portion of the air-conditioning apparatus, andwherein the cover structure includes a corner cover member engaged withthe corner base member adjacent to a longitudinal end of the linearcover member.

[0062] The corner base member is adapted or configured typically tocover or is laid on the ends of the linear base and cover members to beengaged therewith, whereupon “cover” or “laid on” refers to a statesuperposed in order on(beneath) the ceiling surface from lower side.However, the corner base member may have a side edge situated closer tothe ceiling surface than at least one of adjacent ends of the linearbase and cover members or as high as the linear base member.

[0063] In a ceiling panel structure according to an embodiment of oneaspect of the invention, in a case where the corner base member coversthe ends of the linear base and cover members, typically, the cornercover member comprises a part of the deflection induction portion whichis substantially rigid against the airflow to deflect a part of theconditioning air, having been blown out through the air-outlet of theair-conditioning apparatus, in a direction away from the ceilingsurface, and the corner cover member has a generally U-shapedcross-section, the corner cover member being engaged with an outwardlyengaging portion of an outer side wall of the corner base member at aninwardly engaged portion of one of two leg parts of the “U”, andcontacting at an inner face of a bottom part of the “U” with anextending end of the deflection induction portion of the corner basemember. Such being case, the corner base member typically comprises aflow-resistant projection, serving as a resistance to reduce the flowrate of the conditioning air flowing along the surface of the cornerbase member, upstream of the deflection induction portion. In this case,the disengagement of the corner cover member from the corner base membercan be made relatively easily.

[0064] A ceiling panel structure according to a typical embodiment ofsaid one aspect of the invention is adapted to be mounted to a ceilingat a downstream of a conditioning air-outlet of a ceiling-mountedair-conditioning apparatus, having a room air-inlet at a central portionthereof and the air-outlet at a peripheral portion thereof, the ceilingpanel structure including a deflection induction portion which issubstantially rigid against an airflow to deflect the conditioning air,having been blown out through the outlet of the air-conditioningapparatus, in a direction away from the ceiling, the ceiling panelstructure comprising linear panel structures; and corner panelstructures positioned between adjacent ends of the linear panelstructures and engaged thereto, each linear panel structure comprising abase member capable of being mounted to a surface of the ceiling at oneprincipal face thereof to extend along an associated linear side edge ofthe air-conditioning apparatus and having an adjustable length and widthin the extending direction, the base member having an engaging portionat a principal face opposite to said one principal face, and a covermember of an adjustable length and width adapted to be engaged with theengaging portion of the associated base member at an engaged portionthereof to be fixed thereto, the cover member having a deflectioninduction portion which is substantially rigid against an airflow todeflect a part of the conditioning air, having been blown out throughthe air-outlet of the air-conditioning apparatus, in a direction awayfrom the ceiling, wherein the engaging portion of the linear base membercomprises a pair of engaging recesses spaced and faced away from eachother in a widthwise direction of the linear base member, the pair ofengaging recess portions extending in an extending direction of thelinear base member, one of a pair of engaging recesses having sidewalls, one of the side walls closer to a surface of the ceiling thananother of the side walls having an inclined face inclined to be closerto the ceiling surface as departing more remote from another of the pairof recesses, and wherein the engaged portion of the linear cover membercomprising a pair of engaged projections, engaged with the pair ofengaging recesses of the linear base member, spaced from and faced toeach other in a widthwise direction of the linear cover member, one ofthe projections having a guide part movable along the inclined face ofthe side wall, closer to the ceiling surface, of said one recess.

[0065] Heretofore, description have been made on the basis that theceiling panel structure is mounted on the ceiling at a downstream of theair-outlet of the ceiling-mounted air-conditioning apparatus having theroom air-inlet at the central portion and the conditioning air-outlet atthe peripheral portion. However, the features of the ceiling panelstructure thus described, is also more or less effective in a case wherethe ceiling panel structure is mounted on the ceiling, instead of theouter periphery of the ceiling-mounted air-conditioning apparatus, at adownstream of a conditioning air-outlet of a ceiling-mountedconditioning-air-discharge or blow-out apparatus, having only theconditioning air-outlet(s), i.e., conditioning-air discharge duct havingno air-inlet and the whole aperture of the duct serves for theair-outlet. Therefore, the ceiling panel structure of the invention canbe applied also even to the ceiling-mounted conditioning-air-dischargeapparatus.

[0066] That is, the ceiling panel structure of the invention may be, forexample,

[0067] (1) a ceiling panel structure adapted to be mounted to a ceilingat a downstream of a periphery of a conditioning air-outlet of aceiling-mounted conditioning-air-discharge apparatus, having theair-outlet at a surface of the ceiling, said ceiling panel structurecomprising: at least one base member adapted to be mounted to theceiling at the downstream of the air-discharge apparatus and having anengaging portion at a side opposite to a side faced to the ceiling; andat least one cover member engaged at an engaged portion thereof with theengaging portion of said at least one base member to be fixed thereto,said at least one cover member having a deflection induction portionwhich is substantially rigid against an airflow to deflect a part of theconditioning air, having been blown out through the outlet of theair-discharge apparatus, in a direction away from the ceiling,

[0068] (2) a ceiling panel structure adapted to be mounted to a ceilingat a downstream of a periphery of a conditioning air-outlet of aceiling-mounted conditioning-air-discharge apparatus, having theair-outlet at a surface of the ceiling, said ceiling panel structurecomprising linear panel structures and corner panel structures, whereineach of the linear panel structures comprises a base member capable ofbeing mounted to a surface of the ceiling at one principal face thereofto extend along an associated linear side edge of the air-dischargeapparatus, a length and width of the base member in an extendingdirection thereof being adjustable, the base member having an engagingportion at a principal face thereof opposite to said one principal face,a cover member of an adjustable length and width adapted to be engagedwith the engaging portion of the associated base member at an engagedportion thereof to be fixed thereto, the cover member having adeflection induction portion which is substantially rigid against anairflow to deflect a part of the conditioning air, having been blown outthrough the outlet of the air-discharge apparatus, in a direction awayfrom the ceiling, and each of the corner panel structure is adapted tobe positioned between adjacent ends of the associated linear panelstructures to be engaged with the adjacent ends,

[0069] (3) a ceiling panel structure adapted to be mounted to a ceilingat a downstream of a periphery of a conditioning air-outlet of aceiling-mounted conditioning-air-discharge apparatus, having theair-outlet at a surface of the ceiling, the ceiling panel structureincluding a deflection induction portion which is substantially rigidagainst an airflow to deflect the conditioning air, having been blownout through the outlet of the conditioning-air-discharge apparatus, in adirection away from the ceiling, the ceiling panel structure comprisinga base structure adapted to be mounted to a ceiling at an outside of theair-discharge apparatus and having an engaging portion at a sideopposite to a side faced to the ceiling, the base structure including alinear base member adapted to be mounted to a surface of the ceiling atone principal face thereof to extend along a side edge of theair-discharge apparatus; and a cover structure engaged at an engagedportion thereof with the engaging portion of the base structure to befixed thereto, the cover structure including a linear cover memberadapted to be engaged with the linear base member and having thedeflection induction portion; wherein the engaging portion of the linearbase member comprises a pair of engaging recesses spaced from each otherin a widthwise direction thereof and opened at opposite sides to befaced away from each other, one of the recesses having side walls, oneof the side walls situated closer to the surface of the ceiling thananother of the side walls having an inclined face inclined to be closerto the surface of the ceiling as departing more remote from another ofthe recesses, and wherein the engaged portion of the linear cover membercomprises a pair of engaged projections, to be engaged with the pair ofengaging recesses of the linear base member, at regions spaced from eachother in a widthwise direction of the linear cover member, the pair ofthe engaged projections being situated at sides faced to each other andbeing capable of being displaced resiliently toward/from each other, oneof the projections having a guide part movable along the inclined faceof the side wall, closer to the surface of the ceiling, of said onerecess, or

[0070] (4) a ceiling panel structure adapted to be mounted to a ceilingat a downstream of a periphery of a conditioning air-outlet of aceiling-mounted conditioning-air-discharge apparatus, having theair-outlet at a surface of the ceiling, the ceiling panel structureincluding a deflection induction portion which is substantially rigidagainst an airflow to deflect the conditioning air, having been blownout through the outlet of the conditioning air-discharge apparatus, in adirection away from the ceiling, the ceiling panel structure comprisinglinear panel structures; and corner panel structures positioned betweenadjacent ends of the linear panel structures and engaged thereto, eachlinear panel structure comprising a base member capable of being mountedto a surface of the ceiling at one principal face thereof to extendalong an associated linear side edge of the air-discharge apparatus andhaving an adjustable length and width in the extending direction, thebase member having an engaging portion at a principal face opposite tosaid one principal face, and a cover member of an adjustable length andwidth adapted to be engaged with the engaging portion of the associatedbase member at an engaged portion thereof to be fixed thereto, the covermember having a deflection induction portion which is substantiallyrigid against an airflow to deflect a part of the conditioning air,having been blown out through the air-outlet of the air-conditioningapparatus, in a direction away from the ceiling, wherein the engagingportion of the linear base member comprises a pair of engaging recessesspaced and faced away from each other in a widthwise direction of thelinear base member, the pair of engaging recess portions extending in anextending direction of the linear base member, one of a pair of engagingrecesses having side walls, one of the side walls closer to a surface ofthe ceiling than another of the side walls having an inclined faceinclined to be closer to the ceiling surface as departing more remotefrom another of the pair of recesses, and wherein the engaged portion ofthe linear cover member comprising a pair of engaged projections,engaged with the pair of engaging recesses of the linear base member,spaced from and faced to each other in a widthwise direction of thelinear cover member, one of the projections having a guide part movablealong the inclined face of the side wall, closer to the ceiling surface,of said one recess.

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The foregoing and other objects as well as features of theinvention will be made clearer from the description of preferredembodiments of the invention hereafter with reference to accompanyingdrawings in which,

[0072]FIGS. 1A to 1F are explanatory views for illustrating that aceiling panel structure is mounted according to a shape of aceiling-mounted air-conditioning apparatus, in which FIG. 1A is anexplanatory bottom view of an example of square-shaped air-conditioningapparatus mounted in the ceiling as viewed from a lower position, FIG.1B is an explanatory bottom view of a ceiling panel structure, accordingto one preferred embodiment of the invention, for the air-conditioningapparatus of FIG. 1A, FIG. 1C is an explanatory view showing to adjust,according to a planner (bottom) shape of the ceiling-mountedair-conditioning apparatus, a shape or configuration of the ceilingpanel structure, and FIGS. 1D, 1E and 1F are explanatory bottom views ofexamples of various shapes or types of ceiling-mounted air-conditioningapparatus to which the ceiling panel structure is applied;

[0073]FIG. 1G is an explanatory bottom view of an anemometer type ofair-discharge apparatus to which the ceiling panel structure is applied;

[0074]FIG. 2 is an explanatory bottom view, of the ceiling panelstructure, where the shape and/or the size of thereof are/is changedaccording to presence of an obstacle on the ceiling;

[0075]FIG. 3 is an explanatory oblique view of a ceiling panelstructure, as viewed from an obliquely lower position, according to onepreferred embodiment of the invention;

[0076]FIGS. 4A and 4B are illustrations of a ceiling panel structureaccording to one preferred embodiment of the invention, in which FIG. 4Ais a partially broken explanatory bottom view thereof, and FIG. 4B is anexplanatory side view of thereof as viewed in a direction of an arrowIVB in FIG. 4A;

[0077]FIGS. 5A and 5B are illustrations of a linear panel structure forthe ceiling panel structure of FIG. 4A, in which FIG. 5A is anexplanatory bottom view, and FIG. 5B is an explanatory sectional viewalong a line VB-VB of FIG. 5A;

[0078]FIGS. 6A and 6B are illustrations of a linear base member for thelinear panel structure of FIG. 5A, in which FIG. 6A is an explanatorybottom view and FIG. 6B is an explanatory sectional view along a lineVIB-VIB of FIG. 6A;

[0079]FIGS. 7A and 7B are illustrations of a linear cover member for thelinear panel structure of FIG. 5A, in which FIG. 7A is an explanatorybottom view, and FIG. 7B is an explanatory sectional view along a lineVIIB-VIIB of FIG. 7A;

[0080]FIGS. 8A and 8B are illustrations of a corner panel structure forthe ceiling panel structure of FIG. 4A, in which FIG. 8A is anexplanatory side view as viewed in a direction of an arrow VIIIA of FIG.8B, and FIG. 8B is an explanatory bottom view;

[0081]FIGS. 9A to 9D are illustrations of a corner base member for thecorner panel structure of FIG. 8A, in which FIG. 9A is an explanatoryside view, FIG. 9B is an explanatory sectional view along a line IXB-IXBof FIG. 9C, FIG. 9C is an explanatory bottom view as view in a directionof an allow IXC of FIG. 9A, and FIG. 9D is an explanatory sectional viewalong a line IXD-IXD of FIG. 9C;

[0082]FIGS. 10A and 10B are illustrations of a corner cover member forthe corner panel structure of FIG. 8A, in which FIG. 10A is anexplanatory side view, and FIG. 10B is an explanatory bottom view asviewed in a direction of an arrow XB of FIG. 10A;

[0083]FIG. 11 is an explanatory oblique view, as viewed from anobliquely lower position, for illustrating a mounting process of thecorner cover member to complete the ceiling panel structure of FIG. 4;

[0084]FIG. 12 is an explanatory bottom view illustrating a state wherethe corner cover member of FIG. 11 has been mounted;

[0085]FIG. 13 is a diagrammatic sectional view illustrating a state offlow of conditioning air adjusted by ceiling panel structure accordingto one preferred embodiment of the invention;

[0086]FIG. 14 is a partially broken explanatory sectional view of amodified linear panel structure;

[0087]FIGS. 15A to 15C are illustrations of a modification of the cornerpanel structure, in which FIG. 15A is an explanatory oblique view, of acorner base member thereof serving also as a base for a linear covermember, as viewed from an obliquely lower position, FIG. 15B is anexplanatory oblique view illustrating a mounting process of the linearcover member, and FIG. 15C is an explanatory oblique view illustrating amounting process of the corner cover member;

[0088]FIGS. 16A to 16B are illustrations of a modification of the cornerbase member, in which FIG. 16A is an explanatory oblique viewillustrating an intermediate state, for mounting the corner base member,as viewed from an obliquely lower position, and FIG. 16B is an obliqueview of the corner base member after mounting or assembly of corner basemember;

[0089]FIGS. 17A to 17D are illustrations relating to a modified ceilingpanel structure, in which FIG. 17A is a bottom (plan) view illustratinga mounting process of a corner base member which serves also as a baseof the linear cover member, FIG. 17B is a bottom view illustrating astate where two corner base members have been assembled, FIG. 17C is abottom view illustrating a state where two corner base members have beenconnected with each other through a linear cover member (a state where alinear cover member has been mounted between two corner base members)and, FIG. 17D is an explanatory bottom view illustrating a state justbefore completing of assembly of the ceiling panel structure;

[0090]FIGS. 18A and 18B show a ceiling panel structure according to apreferred embodiment of said one aspect of the invention, in which FIG.18A is a partially broken explanatory bottom view, and FIG. 18B is anexplanatory side view in a direction of an arrow of XVIIIB of FIG. 18A;

[0091]FIGS. 19A and 19B show a linear panel structure for the ceilingpanel structure of FIG. 18A, in which FIG. 19A is an explanatory bottomview, and FIG. 19B is an explanatory sectional view along a lineXIXB-XIXB of FIG. 19A;

[0092]FIG. 20 is an oblique view of a linear base member for the linearpanel structure of FIG. 19;

[0093]FIGS. 21A to 21D are illustrations of the linear base member ofFIG. 20A, in which FIG. 21A is an explanatory bottom view, FIG. 21B isan explanatory sectional view along a line XXIB-XXIB of FIG. 21A, FIG.21C is an explanatory sectional view of a modification of an engagingrecess situated at a widthwise outer end, and FIG. 21D is an explanatorysectional view of a modification of a part of an inclined face;

[0094]FIG. 22 is an explanatory oblique view of a linear cover memberfor the linear panel structure of FIG. 19;

[0095]FIGS. 23A to 23C are illustrations of the linear cover member ofFIG. 22, in which FIG. 23A is an explanatory bottom view, FIG. 23B is anexplanatory sectional view along a line XXIIIB-XXIIIB of FIG. 23A, andFIG. 23C is an explanatory sectional view of a modification of anengaged projection situated at a widthwise outer side;

[0096]FIGS. 24A and 24B are illustrations of a corner panel structurefor the ceiling panel structure of FIG. 18A, in which FIG. 24A is anexplanatory side view as viewed in a direction of an arrow XXIVA of FIG.24B, and FIG. 24B is an explanatory bottom view in a direction of anarrow XXIVB of FIG. 24A;

[0097]FIGS. 25A and 25B are illustrations of, respectively, a cornerbase member and corner cover member for the corner panel structure ofFIG. 24A, in which FIG. 25A is an explanatory oblique view of the cornerbase member, and FIG. 25B is an explanatory oblique view of the cornercover member;

[0098]FIGS. 26A to 26C are illustrations of the corner base member ofFIG. 25A, in which FIG. 26A is an explanatory side view as viewed in adirection of an arrow XXVIA of FIG. 26B, FIG. 26B is an explanatorybottom (surface) view as viewed in a direction of an arrow XXVIB of FIG.26A, and FIG. 26C is an explanatory side view as viewed in a directionof an arrow XXVIC of FIG. 26B;

[0099]FIG. 27 is an explanatory view of an upper face (back) of thecorner base member of FIG. 25A;

[0100]FIGS. 28A to 28C are illustrations of the corner cover member forthe corner panel structure of FIG. 24A, in which FIG. 28A is anexplanatory side view as viewed in a direction of an arrow XXVIIIA ofFIG. 28B, FIG. 28B is an explanatory bottom view as viewed in adirection of an arrow XXVIIIB of FIG. 28A, and FIG. 28C is anexplanatory view of a modification of the engaged projection;

[0101] FIGS. 29 is an explanatory oblique view, as viewed from anobliquely lower position, for illustrating a mounting process of thecorner cover member to complete the ceiling panel structure of FIG. 18A;

[0102]FIG. 30 is an explanatory bottom view illustrating a state wherethe corner cover member of FIG. 25B has been mounted;

[0103]FIGS. 31A and 31B are illustrations of superposed states of thelinear panel structure and the corner panel structure, in which FIG. 31Ais an explanatory sectional view of FIG. 30 along a line XXXIA-XXXIA(whereas the linear panel structure 311D is not shown), and FIG. 31B isan explanatory sectional view, of modification of FIG. 31A, illustratedsimilarly to FIG. 31A;

[0104]FIG. 32 is a diagrammatic sectional view illustrating a state offlow of conditioning air adjusted by ceiling panel structure of FIG. 18Aaccording to the preferred embodiment of said one aspect of theinvention; and

[0105]FIGS. 33A to 33F are illustrations for an end cap structure to befitted to either end of the linear panel structure to provide a linearpanel structure apparatus in a case where the linear panel structure isused independently of the corner member, in which FIG. 33A is anexplanatory plan (upper face) view, FIG. 33B is an explanatory frontview, FIG. 33C is an explanatory bottom view, FIG. 33D is an explanatoryright side view, FIG. 33E is an explanatory rear (back) view, and FIG.33F is an explanatory left side view.

DETAILED DESCRIPTION OF THE PREFFERRED EMBODIMENTS

[0106] Now, ceiling panel structures according to preferred embodimentsof the invention are described in detail referring to accompanyingdrawings.

[0107]FIG. 1A shows a ceiling-mounted air-conditioning apparatus 200mounted in a ceiling surface 201 as viewed from a lower face, i.e.bottom face thereof, FIG. 1B shows a ceiling panel structure 10according to a preferred embodiment of the invention, and FIG. 1C showsa state where the ceiling panel structure of FIG. 1B is mounted aroundthe air-conditioning apparatus of FIG. 1A.

[0108] The ceiling panel structure 10 comprises four linear panelstructures 11, lengths of which are adjustable, and four corner panelstructures 12, each connecting the adjacent linear panel structures 11,11 at respective adjacent ends thereof.

[0109] In a case where the air-conditioning apparatus is of a type 200 ahaving a longitudinally or vertically (in the face of the drawing)elongated rectangular outer shape as shown in FIG. 1E, the ceiling panelstructure 10 is assembled to have a longitudinally or vertically (in theface of the drawing) elongated rectangular shape as shown by animaginary line 10 a in FIG. 1C. On the other hand, in a case where theair-conditioning apparatus is of a type 200 b having a laterally orhorizontally (in the face of the drawing) elongated rectangular outershape as shown in FIG. 1F, the ceiling panel structure 10 is assembledto have a laterally or horizontally (in the face of the drawing)elongated rectangular shape as shown by an imaginary line 10 b in FIG.1C. Meanwhile, in a case where the air-conditioning apparatus is of atype 200 c having a square shape as shown in FIG. 1D, the ceiling panelstructure 10 is assembled to have the corresponding square shape asshown by solid lines in FIG. 1C, while a length of each side of thesquare may be increased or decreased as desired.

[0110] Each linear panel structure 11 of the ceiling panel structure 10comprises, as shown in FIGS. 5A-5B, 6A-6B, and 7A-7B, a linear basemember 20 made of plastic material (FIGS. 5A-5B and 6A-6B), and a linearcover member 40 made of plastic material and coupled to the linear basemember 20 (FIGS. 5A-5B and 7A-7B). In the description of this embodimenthereafter, concrete sizes of various portions or parts are shown, whichare, however, only typical or one of desired examples and the inventionis not limited to the sizes, shapes, or the similar order of sizes orsimilar shapes.

[0111] As shown in FIGS. 6A and 6B, the linear base member 20 comprisesa pate-like portion 21 having a width W1 of about 15 cm and a length L1of about 200 cm. The plate portion 21 comprises a main plate portion 22,of about 3 mm in thickness D1, and a guide plate portion 26 of about 2mm in thickness D2 and of about 9.5 cm in width W2. The guide plateportion 26 has a principal face 24 which is coplanar with one principalface 23 of the main plate portion 22, and extends integrally from oneend 25 of the main plate portion 22.

[0112] The guide plate portion 26 has, in the principal face 24, grooves27 extending over the whole length in the longitudinal direction thereoffor example at regular widthwise intervals of 1 cm. The interval orspacing may be greater or smaller than 1 cm, and may not be uniform orconstant if desired. Therefore, a person or workman who mount theceiling panel structure 10 can adjust by himself at the mounting jobsite the width W2 of the guide plate portion 26 and accordingly thewidth W1 of the base member 20 by producing, in and along a desiredgroove among the grooves 27, a deeper cutting groove by means of edgesof a cutter knife or the like at the job site. A width, depth andcross-sectional shape are not limited so long as the guide plate portion26 can be weakened for facilitating separation along the groove 27within an extent in which there is not a possibility that the guideplate portion 26 may be separated or broken therealong during usualhandling thereof. In this embodiment, a groove 27 a similar to thegroove 27 is formed in another principal face 28, i.e. the surface, ofthe plate portion 26, which facilitate separation, of an edge part whichmay be subjected to damages during transportation thereof etc., beforeuse or application of the member 20 onto the ceiling 200. The groove 27a may be omitted.

[0113] The main plate portion 22 has, on another principal face orsurface 29 of said one end 25, an engagement projection 30 in which oneend 57 (FIGS. 7A-7B) of the cover member 40 is fitted. The engagementprojection 30 comprises a resistive face part 31 rising (depending) fromthe principal face 28 serving as the guide face of the guide plateportion 26 substantially in perpendicular thereto, and a deflectionguide face part 32 of a semi-cylindrical shape (semi-circular shape incross-section) connected continuously and smoothly with the resistiveface portion 31. A recess 33 is formed in the projection 30 to receivetherein an end 57 of the cover member 40 to be engaged therewith. Anopening 33 a of the recess 33 is narrowed for ensuring the engagementwith the cover member 40. The resistive face part 31 and deflectionguide face part 32 may be of any other cross-sectional shape such as apart of ellipse, so long as the projection 30 in the form of a smallprotrusion can serve as a flow-resistant projection to act as aresistance against the conditioning airflow to decelerate the airflow.Similarly, a typical example of vertically downward length or height ofthe resistive face part 31 from the principal face 28 may be about 5mm-about 1 cm. However, the height may be greater than 1 cm or smallerthan 5 mm so long as the projection 30 can serve as the flow-resistantprojection.

[0114] At the other widthwise end 34 of the main plate portion 22, i.e.outer end 34 of the base member 20, the base member 20 has engagingprojections 36, 37 which protrudes from the principal face 28 to form arecess 35 therebetween extending in the longitudinal direction of themain plate portion 22 and serve as the engaging portion. The engagingprojections 36, 37 have, respectively, at inner faces of distal ends orlower ends thereof constituting respective parts of the inner face ofthe recess 35, engaging stops 36 a, 37 a protruding within the recess 35to allow an insertion (engagement) in a direction A1 while regulating anescape (disengagement) of in a direction A2. The main plate portion 22has a projection 38, at a widthwise central region of the surface 29thereof, projecting therefrom and extending in the longitudinaldirection thereof, and an engagement recess 39, in the rear face 23,with which a projections 87, 88 of a corner base member 70 to bedescribed later are engaged. The projection 38 is produced uponformation of the recess 39, and may be omitted. As seen from FIG. 6B, ashape of the linear base member 20 in a cross-section perpendicular tothe longitudinal direction thereof is all the same at any position alongthe length, which is also valid for the linear cover member 40 describedlater in detail.

[0115] Further, the main plate portion 22 has holes H for insertingtherethrough screws for mounting. Although only one hole H is shown inFIG. 6A, the holes H may be formed at shorter intervals in thelongitudinal direction of the main plate portion 22. The hole H may havea frust-conically slanted circumferential wall to receive therein a headof the screw as illustrated in a modified panel structure of FIG. 14, ormay be formed in widthwise different positions of the main plate portion22 unless engagement with the cover member 40 is not adversely affected.

[0116] As shown in FIGS. 7A and 7B, the cover member 40 is made of anelongated plastic member of a width W3 which is about the same as thewidth of the main plate portion 22 of the base member 20, and of alength L3 which is about the same as that (L1) of the base member 20,and comprises, as shown in FIG. 7B, a vertical end wall portion 41extending vertically, a lower end guide portion 43 extending generallyhorizontally from a lower end 42 of the end wall portion 41, a shortvertical wall portion 45 extending vertically from an inner end 44 ofthe lower guide portion 43 approximately perpendicularly thereto, adeflection guide portion 47 extending convexly toward downstream from anupper end 46 of the vertical wall portion 45 and serving as thedeflection induction portion, a semi-cylindrical flow-resistantprojection 49 extending integrally from an upstream end 48 of thedeflection guide portion 47 toward upstream and being convex towarddownward and upstream directions, an upstream-side arcuately curvedguide portion 51 extending integrally toward upstream from an upstreamend 50 of the flow-resistant projection 49 and being slightly upwardlyconvex, and an upstream-side horizontal guide portion 53 extendingsubstantially horizontally from an upstream end 52 of the upstream-sidearcuate guide portion 51. The deflection induction portion 47 comprisesan upstream part 47 a extending generally vertically to provide aflow-resistance, and a downstream part 47 b, for providing theflow-resistance and changing the direction of the airflow to guidedownwardly toward the center of the air-conditioning apparatus 200, thedownstream part 47 b being connected smoothly at an upper end 47 cthereof with a lower end of the upstream part 47 a and extending almosthorizontally. The downstream part 47 b is connected smoothly at a lowerend thereof 46 with the vertical wall portion 45. A vertical height fromthe end 52 of the guide portion 53 to the lower end of the horizontalwall portion 43 is, for example, about 4-5 cm. However, the height maybe greater (e.g., 10 cm or greater) or smaller (e.g. about 2-3 cm orsmaller).

[0117] A rear face parts of regions near the downstream end 50 of theupstream-side arcuate guide portion 51 and near a downstream end 52 ofan upstream-side horizontal guide portion 53, i.e., upper face parts 54shown in FIG. 7B, form a coplanar plane to be closely contacted with thelower principal face 29 of the main plate portion 22 of the base member20. Most of an upper face 55 of the upstream-side horizontal guideportion 53 is connected with the upper face 54 through a small step 56.Therefore, a part, of the upstream-side horizontal guide portion 53,situated closer than the step 56 to the distal end can be bent easily indirections B1 and B2. An edge of the step 56 may be angled or arcuatelycurved. The upstream-side horizontal guide portion 53 is thinned at thedistal end part 57, and a shallow recess 59 is formed in a part of thesurface or lower face between a main part 58 of the upstream-sidehorizontal guide portion 53 and the distal end part 57.

[0118] Therefore, the thinned distal end part 57 can be inserted byforce into the recess 33 of the projection 30 of the linear base member20 (FIG. 6B) while expanding a narrowed opening 33 a of the recess 33 ofthe projection 30 by the thinned distal end part 57 in a state where thedistal end part 57 situated more close to the distal end than the step56 is being bent. After the insertion, the wall part 30 a (FIG. 5B)around the opening 33 a of the recess 33 fits in the recess 59 at theproximal end of the distal end part 57 and can hold the horizontal guideportion 53 including the distal end part 57 in a slightly bent state. Asemi-cylindrical wall portion 49 forming the flow-resistant projectionalso serves for the widthwise bending upon the insertion.

[0119] The upper face 54 has therein a wide recess 60, which is widerthan the projection 38 on the surface 29 of the base member 20 andextends over the whole length in the longitudinal direction, to receivethe projection 38 upon assembling or mounting the cover member 40 to thebase member 20.

[0120] A horizontal reinforcing wall 61 is integrally formed between thedownstream end 48 of the flow-resistant projection 49, i.e., theupstream end 48 of the downstream-side arcuate guide portion 47 and thevertical end wall portion 41. Engaged projections 62, 63 serving as theengaged portion extends integrally and upwards from an upper face of thehorizontal wall 61. The engaged projections 62, 63, i.e., projections tobe engaged , have at respectively distal ends thereof small engaged stopprojections 64, 65, i.e., projections to be engaged to be stopped,protruding opposite directions from each other, i.e., protrudingoutwards relative to each other. Upper ends of the engaged stops 64, 65of the engaged projections 62, 63 are situated slightly below the face54.

[0121] The vertical end wall portion 41 protrudes more upward than theplane 54 just by the thickness D1 of the main plate portion 22 of thebase member 20. When the cover member 40 is mounted on the base member20, an end face 67 of an upper end 66 of the vertical wall portion 41 issubstantially flush with the upper faces 23, 24 of the base member 20.The vertical wall portion 41 is slightly thickened at the upper distalend 66 thereof so that an inner face 68 of the end 66 is pressed againstthe end face 21 a of the plate portion 21 of the base member 20.

[0122] Therefore, when the linear panel structure 11 is prepared andmounted, at first, the base member 20 is prepared to have apredetermined width W1x and a predetermined length L1 appropriated forthe mounted site or position. The predetermined width is, herein,typically a width as wide as possible. The possible widest width enablesto minimize the conditioning air having been blown out through theair-conditioning apparatus 200 to flow along the ceiling surface 201.

[0123] However, as shown by imaginary lines 202 in FIG. 2, for example,there may be a pre-mounted obstacle 202, having been already mounted inthe ceiling surface 201 such as a smoke sensor, an electric wiringconnector and a downward illuminating light, at a region of the ceilingsurface 202 relatively close to the site or area where theair-conditioning apparatus 200 is mounted. Such being the case, thewidth W1x of the base member 20 is adjusted to avoid the obstacle 202 orto fit to the width W3 between the obstacle 202 and the air-conditioningapparatus 200. Typically, the width W1x is approximately the same as thewidth W3 (W1x being nearly equal to W3) but is smaller than W3 (W1x<W3).As a matter of fact, there is substantially no possibility that theobstacle 202 is mounted in the ceiling surface 201 without a substantialspacing therefrom to the air-conditioning apparatus 200 because ofvarious requirements such as the strength of the ceiling surface 201,the mounting structure and convenience of mounting work of each ofvarious obstacles 202, and the function and conveniences of maintenancework of each of the obstacles 202. Therefore, a width W10 (FIG. 6A)between the outer end face 21 a of the main plate portion 22 of theplate portion 21 of the base member 20 and outermost groove 27 b of thegrooves 27 in the guide plate portion 26 is preset to a possible minimumlength considering the above-mentioned situations. Four obstacles 202are shown in FIG. 2, which is, however, exceptional. Normally, therewill be at most one or two regions where obstacles are found.

[0124] When the width W1 of the base member 20 is decreased, a cut-ingroove is formed, in and along an appropriate one of the grooves 27situated at a position providing the width W1 of not greater than awidth W3 but as wide as possible, to be bent therealong for separation.When the widthwise inner edge of the guide plate portion 26 is insertedinto between the ceiling surface 201 and the outer frame or smoothlyplaned board portion of the air-conditioning apparatus 200, the width W1of the base member 20 is selected to be wider by the inserted length.

[0125] Meanwhile, considering use of the corner panel structure 12 to bedescribed later in detail, the base member 20 and the cover member 40are cut to a predetermined length by means of saw or the like. When thedimensions or sizes of the air-conditioning apparatus 200 are relativelystandardized, plural kinds of members 20, 40 of plural lengths may beprepared, and may be cut only when exceptional.

[0126] Upon mounting the linear panel structure 11, at first, the linearbase member 20 is supported at a desired position to be attached to theceiling 201 by means of the screws inserted in the screw holes H. Thelinear base member 20 is thin and light in weight, and can betemporarily fixed to the ceiling surface 201 only by at least twoscrews. Therefore, the linear base member 20 need not be supported orheld by the a workman upon screwing operation of the third or furtherscrew, which can be made easily by the workman even when the workman isforced to have an unnatural posture toward the ceiling surface 201. Inparticular, in a case where the widthwise inner edge of the guide plateportion 26 of the linear base member 20 is inserted into between theceiling surface 201 and the outer frame of the air-conditioningapparatus 200, the member 20 can be provisionally fixed even by thesingle screw.

[0127] Then, the thin walled distal end part 57 of the upstream-sidehorizontal guide portion 53 of the cover member 40 is inserted into therecess 33 of the projection 30 of the base member 20, and the engagedprojections 62, 63 of the cover member 40 are inserted, from the engagedstop parts 64, 65 at the distal end thereof, into the engaging recess 35of the base member 20, while the thin walled distal end part 57 isfurther inserted into depth of the recess 33. Upon the first insertionof the horizontal distal end part 57, the upstream-side horizontal guideplate portion 53 and the flow-resistant projection 49 are bent to beupwardly convexly. The downwardly convex curvature of the flow-resistantprojection 49 of the cover member 40 facilitates the bending deformationin the direction B1. These engagement and insertion are completed, whenthe distal end part 57 of the upstream-side horizontal guide portion 53abuts to the bottom of the recess 33, the distal end of the wall portion30 a of the projection 30 is engaged in the recess 59 in the lower faceof the distal end part 57 of the cover member 40, the upper faces 54, 54at both sides of the upper end opening of the recess 60 abut against theprincipal face 29 of the main plate portion 22 of the base member 20,and the engaged stop projections 64, 65 at the distal ends of theengaged projections 62, 63 are fitted into the engaging recess 35through the engaging projections 36 a, 37 a at the lower end opening ofthe recess 35, and further when the inner face 68 of the upper end 66 ofthe vertical end wall portion 41 abuts against the end face 21 a of thebase member 20.

[0128] Each corner panel structure 12 of the ceiling panel structure 10comprises, as shown in FIGS. 8A-8B, 9A-9D and 10A-10B, a corner basemember 70 (FIGS. 8A-8B and 9A-9D) of plastic material and a corner covermember 90 (FIGS. 8A-8B and 10A-10B) of plastic material coupled to thecorner base member 70.

[0129] The corner base member 70 comprises a generally square andhorizontal top plate-like portion or top plate portion 57 to be closelycontacted upon mounting at an outer principal face 71 thereof with theceiling surface 201, and a vertical side wall portion 73 extendingdownwards from the horizontal top plate portion 72 in perpendicularthereto. The corner base member 70 is of a mirror symmetrical shapeabout a virtual plane which includes the diagonal line D of the topplate portion 72 and extends perpendicularly thereto. The vertical sideplate portion 73 have linear or plate-like side wall portions 77, 78extending along two sides 75, 76 at both sides of a arcuately curvedcorner 74 of the horizontal top plate portion 72, and an arcuate cornerside wall part 79 along the arcuate corner 74 between the plate-likeside wall portions 77, 78. Ends 77 c, 78 c of the side wall portions 77,78 protrude from associated sides or edges 80, 81 of the horizontalplate portion 72.

[0130] The top horizontal plate portion 72 has, as shown FIGS. 9A-9D,engaging wall portions 82, 83 and 84, 85 of a width W5 extendingdownwards from respective edges 80 and 81 and serving as the engagingportions. The wall portions 82, 83 and 84, 85 have, at respective outersides thereof, projecting engaging stop parts, i.e., projections forstop, 82 a, 83 a and 84 a, 85 a. The plate portion 72 has also slits orgrooves 82 b, 83 b and 84 b, 85 b for facilitating bending of the wallportions 82, 83 and 84, 85 while avoiding concentration of the stressesto the proximal ends thereof, and allowing the insertion of engagedportions (to be described later) of the cover member 90, and slits 82 c,83 c and 84 c, 85 c connected to the slits 82 b, 83 b and 84 b, 85 b sothat the wall portions 82, 83 and 84, 85 can be bent uniformly over thewhole width. Reference numeral 86 denote an elongated hole for insertionof the screw.

[0131] In addition, the horizontal plate portion 72 has thin protrusionstrip parts 87, 88 of a width Wb protruding respectively from the edges80, 81. The protrusion strip parts 87, 88 have a cross-sectional shape(a trapezoidal end face being shown in FIG. 9A) substantially identicalwith that of the recess 39 of the linear base member 20 to be insertedthereinto and engaged therewith to assist firm couplings between thecorner base member 70 and the associated linear base members 20 uponassembling the ceiling panel structure 10.

[0132] The horizontal plate portion 72 has grooves 89, similar to thegrooves 27 of the linear base member 20 but in the form of a lattice, ina lower principal face (surface) 72 a thereof near a corner portionwhere the edges 80, 81 are crossed. A group of grooves 89 a, extendingvertically in FIG. 9C, among the grooves 89 serve as the weakened partswhere a width or size or mounting position in the lateral or horizontaldirection in FIG. 9C is adjusted, while a group of grooves 89 b,extending horizontally in FIG. 9C, among the grooves 89 serve as theweakened parts where a width or size or mounting position in thevertical direction in FIG. 9C is adjusted.

[0133] The corner cover member 90 is engaged with and fixed to thecorner base member 70 to provide a surface configuration or shape havingflow-guide, flow-resistant and deflection functions similar to thelinear cover member 40 with respect to the conditioning airflow.

[0134] In addition, the corner cover member 90 of this embodiment has anupper surface 91 of a configuration substantially the same as orcomplementary with that of the lower surface of the linear panelstructure 11 in the side view or side section as in FIG. 10A so that thecorner cover member 90 can be laid on the end portion of the linearpanel structure 11 from the lower side to cover the end portion thereof.A wall 92 of the corner cover member 90 has typically substantially auniform thickness of, for example, about 2-3 mm, and therefore a lowersurface 93 of the wall has approximately the same configuration or shapeas that of the surface of the linear panel structure 11 and hassubstantially the similar flow-resistant, deflection and guidefunctions.

[0135] The corner cover member 90 comprises a flat plate portion 94having a flat surface part 91 a superposed on the lower surface 72 a ofthe top plate portion 72 of the corner base member 70, a downwardlyconvex upstream flow-resistant projection 95 having a concave surfacepart 91 b superposed on the surface of the flow-resistant projection 30of the linear base member 20, an upstream arcuate guide portion 96having an arcuate surface part 91 c superposed closely on the surface ofthe upstream arcuate guide portion 51 of the linear cover member 40, adownwardly convex intermediate flow-resistant projection 97 having aconcave surface part 91 d superposed closely on the surface of theflow-resistant projection 49 of the linear cover member 40, a deflectioninduction portion 98 serving as the concave deflection induction portionand having convexly arcuate surface part 91 e superposed closely on thesurface of the deflection induction portion 47 of the linear covermember 40, a vertical wall portion 99 having a vertical face part 91 fsuperposed closely on the vertical face of the vertical wall portion 45of the linear cover member 40, and a lower end guide portion 100 havinga horizontal face part 91 g superposed closely on the lower horizontalsurface of the horizontal lower end guide portion 43 of the linear covermember 40.

[0136] The corner cover member 90 has, similarly to the corner basemember 70, a mirror-symmetrical shape about a virtual vertical planepassing through the virtual diagonal line D. Therefore, aflow-resistant, deflection-guide and flow-guide portion 101 includingthe wall portions 95, 96, 97, 98, 99, 100, as seen from plan view ofFIG. 10B, comprises two linear flow-resistant, deflection-guide andflow-guide portions 101 b, 101 b along two sides extending in directionsof 90 degrees relative to each other, each of the portions 101 b beingconstituted by linear portions 95 b, 96 b, 97 b, 98 b (not shown), 99 b(not shown) and 100 b, and an arcuate flow-resistant, deflection-guideand flow-guide portion 101 c constituted by circular arc portions 95 c,96 c, 97 c, 98 c (not shown), 99 c (not shown) and 100 c extending over90 degrees to connect smoothly the two linear portions 101 b, 101 b at acorner portion. The arc may be a part of ellipse or the like instead ofa part of the circle.

[0137] The corner cover member 90 includes four engaged projections 102,103 and 104, 105 having respectively engaged stop parts 102 a, 103 a and104 a, 105 a to be engaged and stopped by the engaging stop parts 82 a,83 a and 84 a, 85 a of the engaging projections 82, 83 and 84, 85 of thecorner base member 70. The engaged stop parts 102 a and 104 a haverespectively elongated opposite protrusions 102 b and 104 b for guidingpositioning or registration of the corner cover member 90 upon theengagement. The engaged projections 102, 103 extend from a positioninwardly away from the edge 106 by a distance C in parallel with thelinear flow-resistant guide part 101 b over a region of a width W7(=W5). similarly, the engaged projections 104, 105 extend from aposition inwardly away from the edge 107 by the distance C in parallelwith another linear flow-resistant guide part 101 b over a region of thewidth W7 (=W5). Parts 108, 109 of the corner cover member 90 situatedwithin the distance or width C respectively from the edges 106, 107 issuperposed on the surfaces near the adjacent longitudinal ends or edgesof the linear panel structures 11 to hide the longitudinal edgesthereof.

[0138] In addition, the corner cover member 90 has four engaged stopprojections 112, 113 and 114, 115 serving as the engaged portion atpositions respectively inside of the edges 110 and 111 of the horizontalbottom wall portion 100 by a distance or width W8. In the illustratedembodiment, number of each of the projections 113, 115 are two. Theengaged stop projections 112-115 abut against inner faces 77 b and 78 bof the side walls 77 and 78, when surface parts 116 and 117 of thehorizontal bottom wall portions 100 outside the projections 112, 113 and114, 115 abut against lower end faces 77 a and 78 a of the side walls 77and 78 of the corner base member 70, thereby positioning and fixes thecorner cover member 90 to the corner base member 70 cooperatively withthe above-mentioned engaged projections 102, 103 and 104, 105.

[0139] The corner cover member 90 has, in a rear face (upper face) 91 aof the horizontal plate portion 94, grooves 118 in the form of a latticesimilarly to the grooves 89 of the corner base member 70 and at the sameintervals as that of the grooves 89. In the illustrated embodiment, acorner is cut out in the form of a square cut-out portion 119, definedby a vertically extending groove 118 a and a laterally or horizontallyextending groove 118 b in FIG. 10B, in which the corner of theair-conditioning apparatus 200 can just fit.

[0140] Before mounting the corner cover member 90, each of the cornerbase members 70 is mounted between the adjacent linear base members 20and the ceiling surface 201 in a state where the adjacent projections87, 88 of the corner base member 70 fit in the recesses 39 of theadjacent linear base members 20 (actually and typically, the corner basemember 70 is mounted on the ceiling surface 201 prior to the mounting ofthe linear base member 20 to the ceiling surface 201), and the linearcover members 40 are mounted to the linear base members 20 to form thelinear panel structures 11. Upon mounting the corner cover member 90, asshown in FIG. 11, the corner cover member 90 is mounted to the cornerbase member 70 so that the edge portions 108, 109 cover the adjacentends 11 e, 11 f of the linear panel structures 11, 11, whereupon thecorner cover member 90 is directed, to be fitted, from an inside of thecorner to an outside thereof. Thus, the elongated inclined protrusions102 b, 104 b of the engaged projections 102, 104 of the corner covermember 90 slide along the inclined lower end faces of the engaging stopprojections 82 a, 84 a of the engaging projections 82, 84 of the cornerbase member 70 to be fitted in the outsides thereof. As a result, thestop engagements between the engaged stop parts 102 a-105 a of theengaged portions 102-105 of the corner cover member 90 and theassociated engaging stops 82 a-85 a of the engaging projections 82-85 ofthe corner base member 70 have been established, and, at the same time,the surface parts 116, 117 near ends of the horizontal wall portion 100of the corner cover member 90 and the engaged stop projections 112-115thereof abut respectively against the lower end faces 77 a, 78 a of theside wall portions 77, 78 of the corner base member 40 and the innerfaces 77 b, 78 b thereof thereby positioning and fixing the corner covermember 90 to the corner base member 70 to complete the mounting thereof.

[0141] Now, the overall mounting operation or work of the ceiling panelstructure 10 thus constructed on the ceiling surface 10 is to beexplained.

[0142] At first, the ceiling surface 201 is looked over whether or notthe obstacle(s) is(are) present on the ceiling surface 201 around theair-conditioning apparatus 200.

[0143] We now assume a case where, as shown in FIG. 4A, there is anobstacle 202 a at a position corresponding to the position G in FIG. 2.A width W1x of a linear base member 20R constituting a linear panelstructure 11R to be positioned along the right side in FIG. 4A(hereafter, reference character “R” is attached at the end of referencenumerals to denote that the associated member or element is positionedon the right side) is adjusted depending on the distance W3 between theobstacle 202 a and the adjacent side edge of the air-conditioningapparatus 200 so that the width W1x is not greater than W3 (FIGS. 4A-B).Upon the adjustment, the linear base member 20R is cut along anappropriately positioned groove among the multiple grooves 27 in theplate portion 26R thereof. The cutting operation is carried out withease by cutting in and along the appropriate groove 27 by means of acutter knife or the like, and by bending the member 20R along the cut-inline. In the illustrated embodiment, the obstacle 202 a is situated at aposition extremely close to the air-conditioning apparatus 200 as shownin FIGS. 4A-B, and therefore the linear base member 20R is cut along theinnermost groove 27 b (FIGS. 6A-B) so that the width thereof isminimized. We now assume that there is not any other obstacle on theceiling surface 201 around the air-conditioning apparatus 200.Meanwhile, in a case where there is(are) other obstacle(s) on otherside(s), width(s) of the linear panel structure(s) 11 to be mounted onthe associated side(s) should be adjusted depending on the position(s)of the obstacle(s).

[0144] Then, the workman adjusts positions of the cut-outs in the insidecorners of the corner panel structures 12RU, 12RD (situated respectivelyupper and lower positions on the right side in FIG. 4A, where subscripts“U” and “L” are respectively added to the end of the associatedreference numerals or characters thereof) adjacent to ends of the linearpanel structure 11R. A corner base member 7ORU (not shown) of the rightand upper corner panel structure 12RU is cut along the innermost groove89 a 1 among the grooves 89 a and along the outermost groove 89 b 2among the grooves 89 b in FIG. 9C. A corner cover member 90RU of theupper right corner panel structure 12RU is also cut along the innermostgroove 118 a 1 among the grooves 118 a and along the outermost groove118 b 2 among the grooves 118 b in FIG. 10B. On the other hand, a cornerbase member 7ORD (not shown) of the right and lower corner panelstructure 12RD is cut along the outermost groove 89 a 2 among thegrooves 89 a and along the innermost groove 89 b 1 among the grooves 89b in FIG. 9C. A corner cover member 90RD of the lower right corner panelstructure 12RD is similarly cut along the outermost groove 118 a 2 amongthe grooves 118 a and along the innermost groove 118 b 1 among thegrooves 118 b in FIG. 10B. Thus, the width of the corner panel structure12 at the cut-out portion thereof becomes equal to the associated widthof the adjacent linear panel structure 11, and the freshly formedcut-out portion just fits around the corresponding corner of theair-conditioning apparatus 200.

[0145] Then, the lengths of the linear panel structures 11U, 11D, 11L,11R situated respectively on upper, lower, left and right sides of theair-conditioning apparatus 200 when viewed in FIG. 4A are adjusted orcut according to the lengths of the adjacent sides of theair-conditioning apparatus 200. Upon the cutting, the length of eachlinear panel structure 11 is selected to be shorter than that of theadjacent side of the air-conditioning apparatus 200 by a protrusion orsuperposition length of the corner base member 70 of the corner panelstructure 12 toward or on adjacent to either associated end of thelinear panel structure 11. Actually, the corner base members 70 aremounted in accordance with four corners of the air-conditioningapparatus 200 beforehand. And then, the linear base member 20 ispositioned with respect to two adjacent corner members 70, 70 so thatone end thereof abuts against an associated end or edge of one of thetwo corner base members 70 and is marked at a longitudinal positionthereof which corresponds to the position of an adjacent end of theadjacent other corner base member 70 so that the marked position shouldbe the other end of the linear base member 20, thereby enabling todetermine the length of the linear base member 20 and linear panelstructure 11 without measuring the lengths thereof. Thelength-adjustment of the linear panel structure 11 is carried out forexample by provisionally assembling the linear base and cover members20, 40 of each side into the form of the linear panel structure 11 andthen by cutting the assembly by means of saw or the like. As a matter ofcourse, the linear base member 20 and the linear cover member 40 may becut independently or separately if desired. The length-adjustment of thelinear panel structure 11 may be carried out before the adjustment ofcut-in positions of the corner panel structures 12 or two kinds ofadjustment may be carried out in mixed order.

[0146] Then, each of the four corner base members 70 is fixed to theceiling surface 201 by means of screws or the like through the elongatedscrew holes 86, 86 at a position where the cut-out portion thereof justmatches or fits around the associated corner of the air-conditioningapparatus 200. The screw holes 86 of the corner base member 70 areelongated, so that screwing positions can be selected, within the lengthof the elongated hole 86 for the appropriate screwing while avoidinginappropriate regions therefor of the ceiling surface 201, if any. Inaddition, because the holes 86, 86 of each corner base member 70 areelongated holes extending perpendicularly to each other, the directionof the corner base member 70 can be finely adjusted before tightlyfastening the screws. As a matter of course, any other securing orfastening or fixing means can be used for fixing the corner base member70 if desired.

[0147] Then, each of the four linear base members 20 is pressed againstthe ceiling surface 201 so that either end of the linear base member 20generally abuts the associated side or end face 80 or 81 of each of theadjacent corner base members 70, 70 and so that a part of the recess 39near either end thereof fits around the protrusion 87 or 88 of theadjacent corner base member 70, and therefore each linear base member 20is provisionally fixed to the corner base member 70. The linear basemembers can be then fixed to the ceiling surface 201 by the screwsthrough the screw holes H.

[0148] The thin walled inner ends of the base members 70, 20 may beinserted, if possible, into between the outer frame of theair-conditioning apparatus 200 and the ceiling surface 201. This isexemplified by an illustration shown by dotted lines in FIG. 12. Whenthe thin inner ends J of the base members 70, 20 are thus insertedbetween the outer frame of the air-conditioning apparatus 200 and theceiling surface 201, the air-conditioning apparatus 200 may be pulleddown slightly from the ceiling surface 201, if necessary, to provide agap between the outer frame of the air-conditioning apparatus 200 andthe ceiling surface 201 allowing the insertion of the inner ends Jthereinto. As a matter of course, the width W1x of the linear basemember 20 is adjusted to be wider by a length or width of insertion ofthe inner ends J (in other words, the width of the space where thelinear base member 20 is placed can be smaller than the width W1x of thelinear base member 20 by the insertion length or width). The groove 118of the corner base member 70 to be cut therealong is also selectedconsidering insertion lengths at both sides of the corner portionaccording to the estimated insertion width of the linear base member 20.

[0149] Then, four linear cover members 40 are engaged respectively withthe associated linear base members 20 to be fixed thereto in theabove-mentioned procedures or steps.

[0150] Lastly, four corner cover members 90 are engaged respectivelywith the associated corner base members 70 to be fixed thereto in such amanner that they cover the associated corner base members 70 and theadjacent ends of the linear cover members 40, 40, thereby completing themounting or assembling of the ceiling panel structure 10 in accordancewith the position(s) of the obstacle(s) around the air-conditioningapparatus 200 as shown in FIGS. 4A-B. An example of thus mounted stateof the ceiling panel structure 10 is shown in an oblique view of FIG. 3where the air-conditioning apparatus 200 is not shown.

[0151] As described above, the ceiling panel structure 10 can be mountedwith ease only by adjusting, at the very site of mounting, the widthsand lengths of the linear panel structures 11 and the widths of thecorner panel structures 12 at the cut-out portions thereof according tothe sizes of the air-conditioning apparatus 200 and the distribution ofthe obstacle(s) on or in the ceiling surface 201. The relatively smallsize of corner base members 70 can be fixed with ease to thepredetermined positions by means of screws or the like even by thesingle workman, because the associated corners of the air-conditioningapparatus 200 can be used as positioning guides for mounting the cornerbase members 70. The linear base members 20 can be also positioned andfixed, by screws etc., to the ceiling surface 201 with ease even by thesingle workman, because each of the linear base members 20 can beprovisionally fixed substantially to the corner base members 70, 70 atboth ends thereof by the engagement of the recess 39 with the associatedprotrusion strips 87, 88. If desired, a double-faced adhesive tape orthe like may be put on the rear face of the linear base member 20 uponthe provisional fixing of the linear base member 20 to ensure theprovisional fixation thereof. In addition, the mounting of the linearcover members 40 can be also made with ease even by the single workman,because the mounting of the linear cover members 40 can be actuallycompleted only by engaging them with the associated linear base members20 to be fixed thereto. Furthermore, the mounting of the corner covermembers 90 can be also made with ease even by the single workman,because the mounting of the corner cover members 90 can be completedonly by engaging them with the associated corner base members 70 to befixed thereto. In addition, above-mentioned width- and/orlength-adjustment can be also made with ease even with the saw andcutter knife and even by the single workman.

[0152] Now, the function of the ceiling panel structure 10 upon theoperation of the air-conditioning apparatus is described referring toFIGS. 13 and 4A-B.

[0153] As shown in FIGS. 4A-B, the air-conditioning apparatus 200 ofgenerally rectangular (square) shape along the ceiling surface 201 has aroom-air-inlet 210 at the center of the rectangle andconditioning-air-outlets 211 in the vicinity of four sides or four sideedges thereof. Thus, as shown in FIG. 13, the air-conditioning apparatus200 sucks or intakes the air in a room 207 in a direction K1 from thecentral room-air-inlet 210 by means of a motor-driven fan 212 disposedin a central conduit or passage 205, directs in a direction K2 toward agenerally tubular indoor heat exchanger 213 disposed between the centralconduit 205 and an outer blow-out passage or conduit 206, heats or warms(in case heating-adjustment) or cools (in case of cooling-adjustment)the room air by means of heat medium flowing through heat transmissionpipes of the heat exchanger 213 when the directed air passes throughspaces between the heat transmission pipes and/or heat transmission finsof the heat exchanger 213, and thereafter blows out the air in adirection K3 generally in parallel with the ceiling surface 201 andslightly downwards through the conditioning air-outlet 211 after havingadjusted directions of the airflow by means of desired shapes ofsmoothly planed board or circumferential or side wall 214 and a wind orairflow direction adjustment plate 215 at the conditioning air-outlet211 at a downstream end of the blow-out passage 206. Filters aredisposed, at positions such as an inlet of the airflow flowing into theheat exchanger 213 to pass therethrough, for removing contaminants (suchas very fine particles) in the room air considerably.

[0154] The uppermost layer part of the conditioning airflow having beenblown out through the conditioning air-outlet 211 in outward andslightly downward direction K3 flows generally parallel with the ceilingsurface 201 along the guide plate portion 26 of the linear base member20 of the linear panel structure 11 of the ceiling panel structure 10.The airflow then blows against the flow-resistant projection 30 of thelinear base member 20, and the wind pressure thereof is reduced todecrease the flow rate thereof, while spreading generally over thesurface of the projection 30. The airflow having flown over theflow-resistant projection 30 then flows along the guide portion 51, withthe slightly downwardly curved guide surface, of the linear cover member40 of the linear panel structure 11, and thereafter blows against theflow-resistant projection 49, so that the wind pressure thereof issignificantly reduced to decrease the flow rate thereof. Theconditioning airflow having flown over the flow-resistant projection 49while spreading gradually due to the deceleration thereof is thensignificantly deflected by the deflection guide wall portion 47, whichis curved to project abruptly downwards, i.e., depend downwardssignificantly, into the form of airflow S1, the flow direction of whichhas been changed relative to that of the original airflow out ofair-outlet 211 by an angle of 90 degree or greater. A part of theairflow may flow further over the lower end portion 43, which is howeverdirected substantially inclined downwards.

[0155] The changes in the flow rate and flow direction of theconditioning airflow thus described are mainly typical phenomenaapplicable to the airflow near the surface of the linear panel structure11. The airflow which flows along regions more remote from the surfaceof the linear panel structure 11 is less affected directly by thechanges of the surface configuration of the linear panel structure 11.However, the above-described changes in the conditioning air flow nearthe panel structure 11 more or less affect the airflow of lower regionsor layers to reduce the flow rate, to spread and to be deflected ordirected downwards in the form of the airflow S2.

[0156] On the other hand, the room air is always drawn or suck in thedirection K1 from the air-inlet 210 at the central portion of theair-conditioning apparatus 200. Therefore, a part of the conditioningairflow having been deflected downwards provides a circulation flow asshown by S3 in FIG. 13. This circulation flow S3 significantly reduces,as so-called short-cut or short-circuit, the air-conditioning efficiencyof the air-conditioning apparatus 200 if it becomes excessive. However,it will be acceptable that only a part of the conditioning air is mixedas the circulated flow S3 into the intake flow S4 of the room air.

[0157] Meanwhile, the formation of thus described circulation airflow S3serves or helps, together with the above-mentioned deflected airflow S1,S2, that most of the conditioning airflow may spread as shown by theairflow S5 in FIG. 13 over the room in the desired manner.

[0158] As a result, it can be minimized that the airflow having flownover the lowermost end 43 of the linear cover member 40 of the linearpanel structure 11 flows along the ceiling surface 201 a in contacttherewith at the outside of the panel structure 11. Therefore, it can beminimized that the ceiling surface 201 is smudged or contaminated byfine solid and/or liquid particles contained in the conditioningairflow.

[0159] The role or function of the linear panel structure 11 thusdescribed applies similarly to the corner panel structure 12 because thecorner panel structure 12 has substantially similar cross-sectionalshape or external shape or contour as that of the linear panel structure11. Particularly, in the illustrated embodiment where the air-outlets211 are provided along four sides, if it is hypothetically assumed thatthe corner panel structures 12 are not provided and that there are gapsbetween the linear panel structures 11, 11 instead of the corner panelstructures 12, there would be possibilities that a part of theconditioning air having spread over due to the resistance of the linearpanel structures 11 would flow from ends of the linear panel structures11 into the hypothetical gaps where the corner panel structure 12 areassumed to be omitted, and that such airflow into the gaps may tend togrow or to be accelerated once such airflow has been established. In theceiling panel structure 10 in the form of closed quadrilateral loop,however, such hypothetical airflow into the gaps is eliminated by thecorner panel structures 12 and the flow of the conditioning air towardthe ceiling surface 201 can be minimized as a whole.

[0160] However, in a case where the air-outlet is provided, for example,along two parallel sides or only along one side of the quadrilateralair-conditioning apparatus, the linear panel structure may be mountedonly along the side(s) adjacent and opposed to the air-outlet(s),preferably over a range longer enough than that of the air-outlet. Ifdesired, however, the corner panel structure(s) may be further providedon one or both end(s) of the linear panel structure for suchair-conditioning apparatus. Further, closed quadrilateral ceiling panelstructure may be employed to eliminate the above-mentioned gapsregardless of the number of air-outlets, if desired.

[0161] The structural or constructional features and/or theconfigurational features or shape features of the linear and cornerpanel structures thus described can be changed or modified into variousforms in a case where the length and/or width of thereof can be adjustedwith ease at the mounting job site and especially in a case where theconditioning airflow towards the ceiling surface 201 can besubstantially eliminated. Some of the examples of the modifications ofthe above-mentioned embodiment will now be described briefly.

[0162] In FIG. 14, a modified linear panel structure 11 m is shown. Inthis modification, reference character “m” is added to the end of thereference numerals. The linear panel structure 11 m comprises the singleengaged projection 62 m with a roughened surface instead of the twoengaged projections 62, 63. In addition, inner surfaces of the engagingprojections 36 m, 37 m are roughened instead of the two engagingprojections 36, 37 having the engaging stop protrusions 36 a, 37 a.Thus, way of engagement/fixation of the base member with/to the covermember can be appropriately modified as desired. In addition, the linearcover member 40 m has semi-cylindrical deflection induction portion 45 minstead of the vertical wall portion 45. Thus, faces for providing theflow-resistance, deflection (direction-change) and/or guide function(s)defined by the surface shape or configuration of the cover member 40rigid against the conditioning airflow can be also modified as desired.

[0163] FIGS. 15A-C show an embodiment where the linear panel is formedonly by the linear cover member 40 n having a projection 30 n and plateportion 26 n as well, and where the linear cover member 40 n is engagedwith and fixed to, at either end, a corner base member 70 n. In thisillustrated embodiment, the linear cover member 40 n comprises engagedprojections extending substantially over the whole length thereof to beengaged with and fixed to engaging projections 82 n, 83 n, 84 n, 85 n ofthe corner base member 70 n (in this embodiment or modification,reference character “n” is added to the end of each reference numeral).In this embodiment, the engagement of the engaging projections 82 n-85 nof with the engaged portions of the linear cover member 40 n is selectedto be firm or strong enough to support the relatively long linear covermember 40 n only at both ends thereof. Thus, instead of havingseparately linear panel structures and corner panel structures eachhaving individual base and cover members, the base member of one (i.e.,corner or linear) panel structure may be commonly used for mountingcover member of the other (i.e., linear or corner respectively) panelstructure. This embodiment may be further modified as shown in FIGS.16A-B where reference character “p” is added to the end of eachreference numeral. In the modification of FIGS. 16A and 16B, the cornerbase member 70 p is constituted by combination of plural members 70 p 1,70 p 2, 70 p 3 instead of the single integral member. The corner covermember and the linear cover member may be similarly configured.

[0164] FIGS. 17A-D show a further modification, where a corner basemember 70 q serving for engagement and fixation of both of the cornercover member and the linear cover member are constituted by two parts 70q 1 , 70 q 2 to be engaged with each other along the diagonal line, andare displaced in the longitudinal direction of the linear cover member40 q along an end thereof to be fitted thereto for fixation thereto(reference character “q” is added to the end of each reference numeral).

[0165] The ceiling panel structure 310 according to a preferredembodiment of said one aspect of the invention will now be described indetail referring to FIGS. 18A-B to FIG. 32. In this embodiment,reference numeral “3” is added to the beginning of the referencenumerals or characters of the members, elements or portions of the firstdescribed embodiment generally although some exceptions excepted.

[0166] The ceiling panel structure 310 of FIGS. 18A-B comprises linearpanel structures 311, each of which comprises, as shown in FIGS. 19A-Bto 23A-C, a linear base member 320 of plastic material (FIGS. 19A-B to21A-B) and a linear cover member 340 (FIGS. 19A-B, 22 and 23A-B) ofplastic material coupled to the linear base member 320. In thedescription of this embodiment hereafter, concrete sizes of variousportions or parts are shown, which are, however, only a typical or onedesired examples and the invention is not limited by any means to thesizes, shapes, or the same order of sizes or similar shapes, asdescribed in the first mentioned embodiment.

[0167] The linear base member 320 comprises, as shown in FIGS. 20 and21A-B, a plate portion 321 of a width W1 of about 20 cm and a length L1of about 200 cm at its maximum. The plate portion 321 includes a mainplate portion 322 of a thickness D1 of about 3 mm (FIG. 21B), and aguide plate portion 326 of a thickness D2 of about 2 mm (morespecifically 2.2-2.3 mm or thicker) and of a width W2 of about 10 cmhaving a principal face 324 substantially co-planar with one principalface 323 (face opposed to the ceiling surface 201, i.e., rear face) ofthe main plate portion 322 and extending integrally from one end 325 ofthe main plate portion 322. At least one of the main and guide plateportions 322, 326 may be formed so that the thickness of a part thereofbecomes thinner as approaching closer to an widthwise inner end(right-hand side end in FIGS. 21A, 21B), or both of the main and guideplate portions 322, 326 may have the same thickness.

[0168] The guide plate portion 326 has, in the principal face 324,grooves 327 extending over a whole length in the longitudinal directionthereof, for example, at regular intervals of 1 cm. The interval may begreater or smaller than 1 cm, and may not be uniform or constant ifdesired. Therefore, a workman of mounting work can adjust by himself atthe mounting job site the width W2 of the guide plate portion 326 andaccordingly the width W1 of the base member 320 by producing a cut-ingroove in and along a desired groove 327 among the grooves 327 by meansof edges of a cutter knife or the like at the mounting job site. Awidth, depth and cross-sectional shape are not limited so long as theguide plate portion 326 can be weakened for facilitating separationalong the groove 327 within an extent in which there is not apossibility that the guide plate portion 326 may be separated or brokenduring usual handling thereof. In this embodiment, a groove 327 asimilar to the groove 327 is formed in another principal face 328, i.e.the surface, of the plate portion 326, which facilitate separation, ofan edge part which may be subjected to damages during transportationetc., before use or application of the member 320 onto the ceiling 200.The groove 327 a may be omitted.

[0169] In addition, the guide plate portion 326 has, in the side of theceiling, i.e., rear face 324 thereof, recesses 327 c extending over thewhole length thereof in regular intervals in the widthwise direction,each recess 327 c having about the same depth as that of the grooves 327and a width wider than that of the grooves 327. The recess 327 c is usedfor engagement with an end cap 450 (refer to FIGS. 33A-F) describedlater. The guide plate portion 326 has, on a surface 328 thereof, smallprojections 327 d extending over the whole length in regular intervalsin the widthwise direction thereof, each projection 328 having a heightof the order of 0.1 mm. The projections 327 d mainly for design purposealso serve for a resistance against the airflow to some extent. However,the projections 327 d may be omitted.

[0170] The guide plate portion 326 may have in the surface 328 near thegroove 327 a a projected rib or projection 327 e exaggeratedly shown byimaginary lines in FIGS. 20 and 21A-B. The projection 327 e is taller(e.g., 2 mm high and 1 mm wide) than the above-mentioned projections 327d, and serves for the standard positioning of the linear panel structure311, when the standard width of the structure 311 is mounted on theceiling surface 201. More specifically, in a case where the linear basemember 320 is used, as it is or as cut along the groove 327 a, in astate of standard width (substantially maximum width), a part of theguide plate portion 326 situated closer to the distal end than theprojection 327 e, i.e., distal end portion 326 a between the groove 327a and the projection 327 e, is inserted into a region between the outerframe or smoothly planed board part of the air-conditioning apparatus200 and the ceiling surface 201 to abut the projection 327 e against anouter edge of the smoothly planed board part of the air-conditioningapparatus 200 for the positioning of the linear base member 320, therebyenabling the positioning of the linear panel structure 311. However, thepositioning projection 327 e shown by the imaginary lines may beomitted. In addition, instead of inserting the distal end portion 326 aor the like into between the outer frame or smoothly planed board partof the air-conditioning apparatus 200 and the ceiling surface 201, itmay be simply abutted, as shown in FIG. 30, against the outer side faceof the outer frame or smoothly planed board part of the air-conditioningapparatus 200.

[0171] The main plate portion 322 has at said one end 325 on anotherprincipal face or surface 329 a projection 330 defining a engagingrecess 331 serving as the engagement portion in which a hooked engagedportion 337 (FIGS. 22 and 23A-B) serving as an engaged portion at oneend of the cover member 340 is fitted. As the engaging recess 331 isassociated with the projection 330, the projection 330 is also calledhereafter as the “engaging projection”. Further, herein, i.e., in thisspecification, one of members establishing the engagement relationshipis called as “engaging portion” while another of the members isaccordingly called as “engaged portion”, and therefore, we may call bothmembers as the engaging portion and the engaged portion withoutdistinguishing “engaging portion” and “engaged portion” from each other.This way of naming also applies to engaging relationship of elementsother than the engaging elements 331, 357 in question. The projection330 has an arcuate protrusion wall portion 332 protruding from theprincipal faces 328, 329 to define the recess 331 opened to widthwiseinward co-operatively with the principal face 328 serving as the guideface of the guide plate portion. The engaging recess 331 and arcuateprotrusion wall portion 332 of the projection 330 extend continuouslyover a whole length of the linear base member 320. However, the arcuateprotrusion wall portions 332 may be formed by plural parts each having adesired length in the longitudinal direction and being aligned atregular intervals to define as a whole the engaging recess 331 whichextends almost continuously over the whole length of the linear basemember 320.

[0172] The main plate portion 322 has, at another end 333 thereof or ata widthwise outer end 333 of the linear base member 320, an engagingprojection 335 protruding from the principal face 328 to define anengaging recess 334 opened to a widthwise outer end and to the ceilingsurface 201. Each of the engaging recess 334 and engaging projection 334also extend over the whole length of the linear base member 320 in thelongitudinal direction thereof. Herein, widthwise “outside (or outward)”and “inside (or inward)” as to the linear panel structure 311 or linearbase member 320 means respectively a side more remote from (or a senseof direction away from) the air-conditioning apparatus 200 and a sidenearer to (or a sense of direction approaching to) the air-conditioningapparatus 200 when the element such as the linear panel structure 311,linear base member 320 or linear cover member 340 is disposed in apredetermined orientation relative to the air-conditioning apparatus.The projection 335 comprises, when viewed in a cross-sectional view asshown in FIGS. 19B and 21B, a proximal inclined portion or inclinedguide portion 336 protruding from the principal face 328 to be situatedwidthwise inward as departing more remote from the main plate portion322, a semicircular arcuate portion 336 a curved downwardly convex froma linear extended end of the proximal inclined portion 336 to define arecess 334 together with the proximal inclined portion 336, and a distalinclined portion 337 extending slant and generally parallel with theproximal inclined portion 336 from the arcuate end of the semicirculararcuate portion 336 a. An inner face 336 b of the proximal inclinedportion 336 or ceiling-side wall portion 336 inclined to be closer tothe ceiling surface 201 as departing more remote from the widthwiseinner recess 331, serves as a guide face for engagement or disengagementin directions F2, F1 respectively upon the engagement with ordisengagement from an engaged portion of the cover member 340 to bedescribed later. A widthwise outer end portion or distal end portion 337a of the distal inclined portion 337 is situated widthwise more insidethan a widthwise outer end 333 of the main plate portion 322corresponding to the end of the proximal inclined portion 336, and theouter surface 337 b (a surface opposite to a aide faced or opposed tothe ceiling surface 201) of the distal inclined portion 337 is slantedbe closer to the ceiling surface 201 as departing more remote from therecess 331, thereby serving as a guide face in the direction F1 uponengagement of the cover member 340.

[0173] The main plate portion 322 has, on a widthwise central part ofthe surface 329, a projection 338 extending in the longitudinaldirection thereof and a recess 339 in the rear face 323. As seen fromFIG. 21B, a shape of the base member 320 in a cross-sectionperpendicular to the longitudinal direction thereof is all the same atany position in the longitudinal direction. This is also the case withrespect to the below-described linear cover member 340.

[0174] The main plate portion 322 has further screw holes H for allowinga stem or shaft of mounting screw etc. to pass therethrough. Each hole His elongated to enable to select the screwing position on the ceilingsurface 201. The hole H may have a slanted peripheral recess to receivetherein a head of the screw or may be formed in widthwise different partof the main plate portion 322 unless the engagement with the linearcover member 340 is prevented. The main plate portion 322 of the linearbase member 320 is covered from the downward by the linear cover member340 to be described later so that a surface thereof is hidden.Therefore, the heads of the screws mounted in the main plate portion 322are hidden by the linear cover member 340.

[0175] The cover member 340 is, as shown in FIGS. 22 and 23A-B, made ofan elongated plastic member having a width W3, which is about the sameas that of the main plate portion 322 of the base member 320, and alength L3 which is substantially the same (L3=L1) as the length L1 ofthe base member 320. Herein, i.e., in the specification, unlessmentioned otherwise, “up” and “down” is respectively referred to asbeing a side closer or approaching to and a side more remote ordeparting from the ceiling surface in a condition or state where theceiling panel structure 310 or element(s) thereof is mounted to theceiling surface 201. As shown in FIG. 23B, the cover member 340comprises a vertical inclined end wall portion 341 extending generallyvertically while being slightly slanted to be situated widthwiseoutwards as approaching to the ceiling surface (upwards), a lower endguide portion 343 extending generally horizontally from a lower end 342of the end wall portion or side wall portion 341, a short vertical wallportion 345 extending vertically from an inner end 344 of the lower endguide portion 343 substantially perpendicularly thereto, a deflectionguide portion 347 extending from an upper end 346 of the vertical wallportion 345 to be downwardly convex and serving as the deflectioninduction portion, a downwardly and upstream convex semi-cylindricalflow-resistant projection portion 349 extending upstream from anupstream end 348 of the deflection induction portion 347 and integrallytherewith to provide a resistance against flow of the conditioning airto decelerate it, a slightly upwardly convex upstream arcuate guideportion 351 extending upstream from an upstream end 350 of theflow-resistant projection portion 350 and being integral therewith, anupstream horizontal guide portion 353 extending substantiallyhorizontally from an upstream end 352 of the upstream arcuate guideportion 351, and a hooked end portion 357 formed substantiallycontinuously with an upstream (widthwise inner) end of the horizontalguide portion 353 and serving as the engaged portion to be engaged withthe widthwise inner engaging recess 331 of the base member 320.

[0176] The hooked end portion 357 comprises an inclined wall portion 357b, a generally vertical inclined wall portion 357 c and a generallyhorizontal and tapered small projection 357 d having a wedge-likecross-sectional shape to be fitted in the widthwise inwardly openedengaging recess 331 of the engaging portion 330 of the base member 320.In other words, arcuately projecting wall portion 332 of the engagingprojection 330 of the base member 320 fits in a recess 358 defined bywall portions 357 a-357 d of the hooked end portion. In an assembledstate as shown in FIG. 19B, the hooked end portion 357 serves as aflow-resistant small projection 359 defined by the wall portions 357 cand 357 b. The cross-section of the surfaces of the wall portions 357 cand 357 b may be of any other shape such as a part of ellipse, so longas the small projection 359 acts as the flow-resistant projectionserving as a flow-resistant against the flow of conditioning air todecelerate it. Similarly, although the typical example of the downwardlength or height of the small projection 359 is about 5 mm-about 1 cm,the height may be greater than about 1 cm or smaller than about 5 mm solong as the small projection 359 serves as the flow-resistantprojection.

[0177] The cover member 340 has legs 355, 356 for abutting against thelower principal face 329 of the main plate portion 322 of the basemember 320, on the rear face or upper face 354 in FIG. 23B, at regionsnear the downstream end 350 of the upstream arcuate guide portion 351and near the downstream end 352 of the upstream horizontal guide portion353. In the illustrated embodiment, the leg 355 comprises two leg parts355 a, 355 b, and a recess between the legs 355, 356 receives theprojection 338 of the base member 320. The leg 355 may be omitted.

[0178] The deflection induction portion 347 comprises an upstream part347 a extending generally vertically for providing a flow-resistance andchanging significantly the direction of the airflow, and a downstreampart 347 b connected smoothly at an upper end 347 c thereof with a lowerend of the upstream part 347 a and extending along directionsapproaching the horizontal direction for providing the flow-resistanceand changing the direction of the airflow to guide the airflow downwardsand toward the center of the air-conditioning apparatus 200. Thedownstream part 347 b is connected smoothly at the downstream end 346thereof with the vertical wall portion 345. A vertical height from theend 350 of the guide portion 351 to the lower end of the horizontal wallportion 343 is, for example, about 4-5 cm. However, the height may bemuch greater (e.g., 10 cm or greater) or much smaller (e.g., about 2-3cm).

[0179] As seen from FIGS. 22 and 23B, the linear cover member 340comprises, at a widthwise outer region thereof, a portion 340 u of agenerally “U”-shaped cross-section. That is, the U-shaped portion 340 uis constituted by the horizontal guide portion 343 forming the bottompart of “U”, downstream vertically inclined end wall portion 341 formingone of the two legs of “U”, and the short vertical wall portion 345,deflection induction portion 347 and the semi-cylindrical flow-resistantprojection portion 349 cooperatively forming as a whole another of thetwo legs of “U”. The U-shaped configuration or structure having a cavity340 s between the two legs 341 and 345, 347, 349, i.e., leg 341 and leg345, 347, 349, enables the distance of upper ends of the two legs to beincreased/decreased within an elastic limit of the material therefor,and the distal end 341 a of the outer leg 341 can be elastically orresiliently displaced with respect to the upper end of the inner leg345, 347, 349 to be departed therefrom or to approach thereto in thedirections B1, B2.

[0180] The vertical inclined wall portion 341 at the widthwise outer endof the cover member 340 comprises, at the upper end (ceiling-side end)341 a thereof, a projection 361 projecting widthwise inward. Theprojection 361 serves as an engaged portion 363 to be engaged with theengaging recess 334 of the base member 320. Herein, a recess 362 definedby the projection 361 and wall portion 341 of the cover member 340 maybe regarded as the engaged portion 363 to be engaged with the projection337 of the base member 320 or both of the recess 362 and the projection361 may be regarded as the engaged portion 363.

[0181] A lower face or inner face of the projection 361 is inclined tobe situated lower as going widthwise inward in the embodimentillustrated in FIG. 23B. Instead, the projection 361 may have a lowerface projecting widthwise inward generally horizontally and as shown inan enlarged form of the projection and denoted by reference characters361 a in FIG. 23C, or an upwardly inclined lower face (engaged face)extending to be higher (more upwards) as going widthwise inward, asshown by an imaginary line 361 b in FIG. 23C, so that the disengagementcan be facilitated. In addition, the projection 361 may be shorter solong as the engagement of the cover member 340 can be ensured. Thus, thelength may be, for example, as short as about 1 mm or shorter.

[0182] Upon the mounting, the horizontal wall portion 343 of the covermember 340 is pressed upward V2 in a state where the hooked engagedportion 357 situated at the widthwise inner side of the linear covermember 340 and having the wedge-shaped engaged projection 357 d isengaged with the engaging recess 331 of the widthwise inner engagingportion 330 of the linear base member 320, and where the upper end 341 aof the vertical inclined wall portion 341 situated at the widthwiseouter side of the cover member 340, i.e., the upper face of theprojection 361, abuts against the inclined face 337 b of the inclinedwall 337 of the engaging portion 335 of the base member 340 serving asthe guide part, thereby deforming as a whole elastically or resilientlythe U-shaped portion 340 u constituted by the wall portions 341, 343,345, 347, 349 so that the wall portion 341 can be moved or expanded inthe direction B1 to displace or move the guide part or slide-contactpart 341 a at the upper end of the widthwise outer and almost verticallyinclined wall portion 341 of the cover member 340 in the direction F1along the inclined face 337 b of the inclined wall portion 337 of theengaging portion 335 of the base member 320. When the inwardly directedprojection 361 is widthwise outward beyond the distal end 337 a of theinclined wall portion 337, the projection 361 then abuts against theupper inclined wall 336 of the base member 320, whereupon the upwardlypressing force on the cover member 340 is weakened or removed to enablethe wall portion 341 of the U-shaped portion 341 u of the cover member340 to restore to the original shape or widthwise original position dueto the elasticity or resiliency of the wall portions 341, 343, 345, 347,349 of the U-shaped portion. Therefore, the cover member 340 is engagedwith the engaging portion 335 of the base member 320 in such a mannerthat the projection 361 of the engaged portion 363 thereof fits into theengaging recess 334 of the base member 320 and that the recess 362 fitsaround or receive therein the projection 337 of the base member 320.This engagement action or operation may be carried out all over thelength of the linear base and cover members 320, 340 substantiallysimultaneously or may be proceeded sequentially or gradually from onelongitudinal ends thereof to the other longitudinal ends.

[0183] On the other hand, upon disengagement or removal, operationsreverse to the mounting or engaging operations are carried out. That is,the wall portion 343 etc. are pressed upward in the direction V2 todeform elastically or resiliently as a whole in the B1 direction theU-shaped portion 340 u constituted by the wall portions 341, 343, 345,347, 349 so that the wall portion 341 of the U-shaped portion 341 u ofthe cover member 340 is expanded or displaced in the direction B1,thereby releasing the engagement of the engaged portion 363 with theengaging portion 335, and then the wall portion 341 of the cover member340 is pulled down in the direction V1. Thus, the engagement of theengaged portion 363 of the cover member 340 with the engaging portion335 of the base member 320 is completely released. Then, the engagementof the engaged portion 357 of the cover member 340 with the engagingportion 330 of the base member 320 is released.

[0184] In a case where relatively large force or pressure is requiredfor expanding the U-shaped portion 340 u of the linear cover member 340in the direction B1, the wall portion 343 etc. are pressed upwards inthe vicinity of one longitudinal end of the linear cover member 340 toexpand the end 341 a in the direction B1 or F1 along the inclined face336 b of the upper inclined wall portion 336 and, while keeping theexpanded condition thereof, a distal end of an elongated rod-like partsuch as a screw driver or an other appropriate tool having a strip-likeor thin and elongated plate part is inserted into a gap between thedistal end 337 a of the lower inclined wall portion 337 of the engagingportion 335 and thus expanded engaged projection 361 of the engagedportion 363 and is then moved along the longitudinal direction of thelinear base and cover members 320, 340 toward the other longitudinalends thereof, so that the engagement between the engagement portions335, 363 can be completely released as if the portions 335, 363 arepeeled off from each other. When the projection 361 is configured asshown in FIG. 23C, the engagement can be released easily. The lower wallportion 337 of the engaging recess 334 of the engaging portion 335 ofthe base member 320 may have an inner face extending generallyhorizontally or slanted downwards widthwise outwardly as shown in FIG.21C to facilitate the release of the engagement while ensuring secureengagement.

[0185] Further, as shown in an enlarged view in FIG. 21D, the basemember 320 may have a step 336 c at the inclined face 336 b of theinclined wall portion 336 so that the distal end projection 361 of thewall portion 341 may be engaged once with the step 336 c along the wholeregion in the longitudinal direction when the wall portion 341 of theU-shaped portion 340 u of the cover member 340 is expanded in thedirection F1 or B1, and so that the engaged portion 363 of the covermember 340 can be, thereafter, completely disengaged from the engagingportion 335 of the base member 320 by drawing or pulling down the endwall 341 of the cover member 340. In FIG. 21D, an imaginary line 337 adenotes a widthwise position of the distal end 337 a of the shortinclined wall portion 337 which will be situated outside of the lowerend of a region shown in the enlarged view of FIG. 21D.

[0186] In each of the illustrated embodiments, the short and longinclined wall portions 337, 336 of the base member 320 guide the engagedportion 363 of the cover member 340 upon the engagement, while the longinclined wall portion 336 of the base member 320 guides the engagedportion 363 of the cover member 340 upon the release of the engagement,thereby enabling to engage/disengage of the cover member 340 with/fromthe base member 320 easier, even in a case where only one workman has tocarry out the engagement/disengagement while keeping an unnaturalposture facing upward to the ceiling surface 201.

[0187] Thus, the downstream (widthwise outer) engaged portion 363 of thecover member 340 is engaged with the downstream (widthwise outer)engaging portion 335 of the base member 320 while the wedge-shapedengaged projection 357 d of the upstream (widthwise inner) engagedportion 357 of the cover member 340 is kept to be engaged with theengaging recess 331 of the upstream (widthwise inner) engaging portion330 of the base member 320.

[0188] Now, the corner panel structure 312 of the ceiling panelstructure 310 is to be described with reference to FIGS. 24A-28C. Asshown in these drawings, the corner panel structure 312 comprises acorner base member 370 (refer to FIGS. 24A-27) of plastic material, anda corner cover member 390 (refer to FIGS. 24A-B, 25B and 28A-C) ofplastic material coupled to the corner base member 370.

[0189] In the corner panel structure 312 shown in FIGS. 24A-28C, thecorner base member 370 are configured or adapted to be laid on theadjacent longitudinal ends of the linear panel structures 311 to beengaged therewith (refer to FIGS. 29-31A). The corner base member 370itself has a surface configuration or contours providing flow-guide,flow-resistance and deflection (change of direction of flow) functionssimilar to the whole linear panel structure 311.

[0190] More specifically, the corner base member 370 of generally squareshape in a plan view includes an upper surface 371 having two side edges382 a, 382 b extending at right angle relative to each other and beingconfigured to be complementary in shape with that of the lower surfaceof the linear panel structure 311 (refer to FIGS. 31A-B and 26A-C) sothat the corner base member 370 can be put, from the lower side, on thelongitudinal ends 311 a, 311 a (refer to FIGS. 19A, 29 and 30) of thelinear panel structure 311 to cover the longitudinal ends 311 a, 311 a.As seen from FIG. 26A, a wall 372 of the corner base member 370 hastypically substantially a uniform or constant thickness of, for example,about 2-3 mm except a part thereof. Therefore, a lower surface 373 ofthe wall 372 is configured generally similarly to the surface of thelinear panel structure 311 and has substantially the same flow-guide,flow-resistance and deflection functions with respect to theconditioning airflow.

[0191] The corner base member 370 comprises a corner base body portion380 and a corner base outer frame portion 384 integral with corner basebody portion 380. The corner base body portion 380 comprises aplate-like member of typically generally uniform thickness and of squareshape in a plan view, in which one corner part 381 a of the square iscurved in the form of circular arc.

[0192] The corner base body portion 380 is configured mirror-symmetricalabout a virtual plane including a diagonal line D, passing through bothof the arcuately curved corner 381 a and an opposite corner 381 b cutout in the form of small square, and extending in perpendicular to aplane (plane of FIG. 26B) of the body portion 380. Sides or edges 382 a,382 b including the corner 381 b are superposed on the adjacent edges orends 311 a, 311 a of the adjacent linear panel structures 311, whilesides or edges 382 c, 382 d including the curved corner 381 a areconnected integrally with the corner base outer frame portion 384.

[0193] The corner base body portion 380 comprises a plate portion 374having a plane surface part 374 u superposed on the lower face 328 ofthe guide plate portion 326 of the linear base member 320 of the linearpanel structure 311, a downwardly convex upstream flow-resistantprojection portion 375 having a concave surface part 375 u complementaryin shape with the surface of the flow-resistant projection portion 359of the linear cover member 340 of the linear panel structure 311 to beexactly superposed thereon, an upstream arcuately curved guide portion376 having an arcuate surface part 376 u complementary in shape with thesurfaces of the plate portion 353 and upstream arcuate guide portion 351of the linear cover member 340 to be exactly superposed thereon, adownwardly convex flow-resistant projection portion 377 of circular arccross-sectional shape having a concave surface part 377 u complementaryin shape with the surface of the flow-resistant projection portion 349of the linear cover member 340 to be exactly superposed thereon, and anupstream deflection induction portion 378 serving as a part of theconcave deflection induction portion having a convexly arcuate surfacepart 378 u complementary in shape with the deflection induction portion347 of the linear cover member 340 to be exactly superposed thereon.Each portion 375, 376, 377, 378 has, in a plan view (strictly, bottomview) of FIG. 26B linearly extending parts 375 a, 376 a, 377 a, 378 aand 375 b, 376 b, 377 b, 378 b, and a circular arc part 375 c, 376 c,377 c, 378 c connecting the linearly extending parts smoothly with eachother.

[0194] In addition, the corner base body portion 380 has legs 383 in theform of a rib extending from a rear face (upper face) thereof to supportthe plane of the body portion 380 in parallel with the ceiling surface201. In an embodiment illustrated in FIG. 27, the legs 383 comprisesthree leg parts 383 p, 383 q, 383 r. Each leg part 383 p, 383 q, 383 rextends, in the plane of FIG. 27, in a pattern of “L”, while leg parts383 p, 383 q are arcuately curved around regions crossing the virtualdiagonal line D. Number of leg parts constituting legs 383 may be muchmore or much less than three, and may be intermittently distributedinstead of being continuously extended.

[0195] A plate portion 374 providing most upstream guide face of thecorner base member 380 is generally square, and has, at a sidecorresponding to the circular arcuate corner part 381 a of the bodyportion 380, a similar circular arcuate corner part 374 r (of smallerradius) and a cut-out part 374 c defined by cut-out lines 374 a, 374 bat a corner corresponding to the cut-out corner 381 b of the bodyportion 380. In addition, the plate portion 374 has a square leg part383 s protruding from the side of the upper face 374 u at the cut-outpart 374 c. The square leg part 383 s is connected integrally at twoside edges thereof with the cut-out edges 374 a, 374 b of the plateportion 374, and defines, cooperatively with the other leg parts 383 p,383 q, 383 r, a leg face or abutting plane of the corner base member 380with respect to the ceiling surface 201.

[0196] Further, the plate portion 374 has, in the upper face 374 uthereof, grooves 374 g at regular intervals, serving as the weakenedparts for facilitating cutting thereof for size-adjustment, similarly tothe grooves 327 of the guide plate portion 326 of the linear base member320 of the linear panel structure 311, and a rib-like projection 374 p,on the lower face thereof 374 d, similar to the projection 327 d of theguide plate portion 326 of the linear base member 320.

[0197] The corner base member 370 includes a support wall 378 s,extending continuously from the end of the upstream deflection inductionportion 378 and having an extended end (lower end) 378 t for supportingthe corner cover member 390, at a region except for the regions near theedges 382 a, 382 b superposed on the edge 311 a of the linear panelstructure 311. A cut-out portion 378 f is defined by an end 378 w of thesupport wall 378 s and the lower end 378 u of the upstream guide portion378 of the deflection induction portion. The cut-out portion 378 fallows the downstream part 347 b of the deflection induction portion 347and the vertical guide portion 345 of the linear panel structure 311 tobe projected therethrough slightly downwardly at the ends 311 a thereof(FIG. 31A), when the corner base member 370 is superposed on the linearpanel structure 311.

[0198] The corner base outer frame portion 384 comprises, when view in aplane parallel with an extending plane of the corner base body portion380 (e.g., FIG. 26B), an outer frame body portion 385 extendinggenerally in the form of “L” along the two right-angled side edges 382c, 382 d, of the body portion 380, connected to each other at thearcuate corner 381 a. More specifically, the outer frame body portion385 comprises a linear part 385 b, 385 a extending parallel with thesides 382 a, 382 b, and an arcuate part 385 c between the two linearparts 385 a, 385 b. The parts 385 a, 385 b and 385 c of the outer framebody portion 385 are integrally connected at respective lower endsthereof with linear parts 378 sa, 378 sb and an arcuate part 378 sc ofthe vertically extending wall 378 s of the corner base body portion 380through the corresponding linear parts 386 a, 386 b and arcuate part 386c of a horizontal connection portion 386. End faces 386 at and 386 bt(not shown) of the horizontal connection portion 386 is also cut out tobe substantially flush with the end face 378 w. The outer frame bodyportion 385 is inclined to spread out slightly from the lower endthereof toward the upper end to be situated more remote from theair-conditioning apparatus 200 as approaching to the ceiling surface 201similarly to the vertical inclined wall portion 341 of the linear covermember 340 of the linear panel structure 311, and has a wide leg part387 at the upper end thereof. The leg part 387 adapted to abut againstthe ceiling wall 201 at the upper end has also linear parts 387 a, 387 band an arcuate part 387 c therebetween to be configured, in its planview, in the form of “L”. Reference characters 384 h, 384 g, 384 sdenote respectively a screw hole for mounting the corner base member370, a recess for allowing a tool such as a screw driver to be insertedthereinto for mounting/removing the screw through the screw hole 384 h,and a partially cylindrical wall part defining therein the recess 384 g.It is preferred that each screw hole is configured in the form ofelongated hole or elongated-circular hole 384 hi as shown by animaginary line for one of the holes in FIGS. 26B and 27 to enhance adegree of freedom for selecting the mounting position of the ceilingpanel structure 310 on the ceiling surface 201 without consideringpositioning thereof relative to support frames at the back of, i.e.behind, the ceiling. Such being the case, associated screw-mounting toolinsertion recess 384 gi and recess-defining wall portion 384 si are alsoshaped, as a matter of course, into an elongated-circular form as shownby the imaginary lines.

[0199] The leg part 387 of the corner base outer frame portion 384extends to a region to flush with the edges 382 a, 382 b of the cornerbase body portion 380 so that free ends 387 ae, 387 be of the linearparts 387 a, 387 b defining both sides or legs of “L” are engagedrespectively with adjacent edges 333 of the linear base members 320 ofthe linear panel structures 311. Meanwhile, as shown in FIG. 31B, thefree ends 387 ae and 387 be (not shown) of the leg part 387 may be cutto be flush approximately with the end face 386 at and 386 bt (notshown). In addition, the body portion 385 of the corner base outer frame384 has thin walled protrusions 385 at, 385 bt protruding from the freeends 385 ae, 385 be of the linear part 385 a, 385 b so that they may beslightly inserted into recesses between wall portions 341, 347 definingthe two leg parts of the U-shaped portion 340 u of the linear covermember 340 of the linear panel structure 311. However, there may be apossibility that the thin wall protrusions 385 at, 385 bt may prevent oraffect adversely the ease of mounting the corner base member 370 and,therefore, there are not a few configurational cases where theprotrusions 385 at, 385 bt should be omitted. Thus, in a case where theprotrusions 385 at, 385 bt are formed, the lengths thereof should beminimized or the corner thereof should be preferably cut obliquely toenable the mounting/detaching of the corner base member 370 with ease,in comparison with the projections 385 at, 385 bt exaggeratedly largelyshown in the illustrated embodiment. In this connection, FIG. 31A showsan example in which the thin wall protrusion 385 at is formed while FIG.31B shows an example in which the protrusion 385 at is omitted. Thecorner base outer frame portion 384 further comprises, at an outer faceof the body portion 385 thereof, an engaging recess 389 (FIG. 25A) withwhich the corner cover member 390 is engaged. In an embodimentillustrated in FIG. 26C, the engaged recesses 389 a and 389 b (notshown) at both ends are configured in the form of recess in free ends ofthe outer frame body part 385, while each of intermediate cut-out 389 cand 389 d (not shown) is configured in the form of an aperture. However,for facilitating the mounting/detachment of the corner cover member 390,each cut-out part 389 c, 389 d may be in the form of a shallow groovewhere one of the two cut-out parts or grooves may be omitted. Thearrangement thereof can be determined according to the number thereof.Further, each of the engaging recesses 389 a and 389 b (not shown) atboth ends may be configured in the form of an aperture enclosedcompletely by a circumferential wall thereof instead of the cut-out partopened at least one side thereof.

[0200] The corner cover member 390 comprises, as shown in FIGS. 28A-B,25A-B and 24A-B, a corner cover body portion 391 having as a wholegenerally L-shaped configuration and U-shaped cross-section, whereas oneof two legs of “U” is much shorter than the other of the two legs. Thebody portion 391 comprises a generally L-shaped long outer wall portion392, a generally L-shaped end wall portion 393 extending from one(lower) end of the outer wall portion 392 almost in perpendicularthereto (at a slightly obtuse angle), and a generally L-shaped shortinner wall portion 394 extending from one (inner) end of the end wallportion 393 generally in perpendicular thereto. More specifically, asshown in FIGS. 28A-B, the outer, end and inner wall portions 392, 393,394 have respectively two linear wall parts 392 a, 393 a, 394 a and 392b, 393 b, 394 b and circular arcuate wall parts 392 c, 393 c, 394 cconnecting the associated two linear wall parts 392 a, 393 a, 394 a and392 b, 393 b, 394 b at regions therebetween. The outer wall portion 392has, at an inner edge of the upper end thereof, an engaged projectionportion 395 to be engaged with the cut-out portion 389 of the cornerbase member 370. In the illustrated embodiment, the projection portion395 comprises the substantially the same shape of projections 395 a, 395b protruding at an acute angle relative to the outer wall portion 392and substantially the same shape of projections 395 c, 395 d protrudingat approximately right angle relative thereto to be engaged respectivelywith the cut-out parts 389 a, 389 b (not shown), 389 c and 389 d. One ofthe projections 395 c, 395 d may be omitted for facilitating detachmentof the corner cover member 390, if desired. In addition, the innerprojections 395 c, 395 d may be configured in the form of an arcuateprojection 395 f projecting at an obtuse angle relative to the outerwall part 392 as shown in FIG. 28C to facilitate release of theengagement.

[0201] The corner cover body portion 391 has, on an inner face of theend face 393 thereof, a thin side wall 396 extending in the form of “L”and being spaced by a generally constant distance from the inner wallportion 394. Reference characters 396 r denotes a rib supporting theside wall 396. The side wall 396 terminates before reaching to regionswhere the corner cover body portion 391 covers the adjacent linear panelstructures 311. The inner side wall 396 may be omitted. The end wall ofthe corner cover body portion 391 abuts against the lower end 378 t ofthe extended wall part 378 s of the corner base member 370 when thecorner cover member 390 is put on the corner base member 370.

[0202] The L-shaped inner wall portion 394 of the corner cover bodyportion 391 comprises a band-like edge 394 u bent outward (toward insideof “U”) at upper parts of thereof. The band-like edge 394 u facesthrough a narrow gap to the wall part 378 s extended from the lower endof the arcuate deflection wall portion 378 of the corner base member370, when the corner cover member 390 is put on the corner base member370, and serves as a lower part of the deflection induction portion. TheL-shaped band-like edge part 394 u comprises, at both of thelongitudinal ends thereof, protrusion walls 394 ut, 394 ut. Theprotrusion walls 394 ut, 394 ut of the inner wall portion 394 areengaged with the downstream part 347 b of the deflection inductionportion 347 of the adjacent ends 311 a of the linear panel structures311 exposed through the cut-out part 378 f of the corner base member370, when the corner cover member 390 is put on the corner base member370 under a state where the corner base member 370 has been already puton the adjacent ends 311 a of the linear panel structures 311. However,the protrusion wall 394 ut may be omitted. The embodiment with the wall394 ut is shown in FIG. 31A, while the embodiment without the wall 394ut is shown in FIG. 31B.

[0203] The corner panel structure 312 is mounted in such a manner as tobe laid on the adjacent linear panel structures 311, 311 after thelinear panel structures 311, 311 of predetermined lengths andpredetermined widths have been mounted at predetermined positions. Morespecifically, at first, the corner base member 370 is attached so thatthe edges thereof 382 a, 382 b are superposed on the adjacent ends 311a, 311 a of the linear panel structures 311, 311 extendingperpendicularly to each other. Thus superposed length of each of theedges 382 a, 382 b of the corner base member 370 on each adjacent end311 a, 311 a of the linear panel structure 311, 311 is selected not tobe greater than a length or distance LE (FIG. 27) from each of thecut-out end 378 w at the cut-out 378 f and the end of the leg 383 toeach associated edge 382 a, 382 b. In other words, what is required isto have at least minimum superposition that should not be greater thanLE. The length LE corresponds to the maximum tolerance (strictly, a halfthereof) for the length of the linear panel structure 311. When thecorner base member 370 is superposed on the linear panel structure 311from the lower side, the corner base member 370 contacts, at the wallportions 374, 375, 376, 377, 378 thereof against the respectivecomplementary configured wall portions 326, 357, 353, 349, 347 a of thelinear panel structure 311 and at the leg 383 thereof against theceiling surface 201, and is engaged at the leg 387 of the outer frameportion 384 thereof with the end 333 of the linear panel structure 311(refer to FIGS. 31A-B). In a case where the thin wall protrusions 385at, 385 bt are provided, for example, the corner cover member 370 isinclined in such a manner that the diagonally outer corner 381 a iscloser to the ceiling surface 201 than the diagonally inner corner 381b, and the legs 387, 387 of the outer frame portion 384 are engaged withthe adjacent ends 311 a, 311 a of the linear panel structures 311, 311while inserting the thin wall protrusions 385 at, 385 bt from thediagonally outer side, and then the diagonally inner corner 381 b isdisplaced closer to the ceiling surface 201 to complete theabove-mentioned superposition. Then, as described above, the cornercover member 390 is superposed on the corner base member 370 so that theengaged projections 395 of the corner cover member 390 can be engagedwith the engaging recesses 389 of the corner base member 370.

[0204] Now, the mounting of the thus constructed ceiling panel structure310 on the ceiling surface is to be described.

[0205] At first, it is looked over whether obstacle(s) is(are) presenton the ceiling 201 around the air-conditioning apparatus 200. Forexample, suppose that an obstacle 202 a is present, at the position G ofFIG. 2, as shown in FIG. 18A. The width of the linear base member 320 isadjusted in the same manner as described with respect to the linear basemember 20 if required. In this example, we assume, as shown in FIGS.18A-B, that the obstacle 202 a is situated remote enough and, therefore,that the linear base member 320R is cut along the widthwise outermostgroove 327 a (FIG. 20 etc.) to have the standard maximum width thereofor can be used or applied to without being cut. We further assume hereinthat there is not any other obstacle 202 on the ceiling surface 201around the air-conditioning apparatus 200. If the other obstacle 202 ispresent, the width of the linear base member 320 of the linear panelstructure 311 to be mounted at the associated position is adjustedutilizing the grooves 327 depending on the position of the obstacle 202.

[0206] Then the lengths of the linear panel structure 311R, 311L, 311Uand 311D are adjusted. More specifically, the linear panel structures311R, 311L, 311U, 311D are respectively cut to be equal to the lengthsof the side edges, of the air-conditioning apparatus 200, along whichthey are disposed. In a case where a part of the linear panel structure331 (e.g., 311U or 311D) is inserted into between the ceiling surface201 and the side wall or smoothly planed board of the air-conditioningapparatus 200, the corner panel structure 312 (e.g., 312RU or 312RD) isshifted in the vertical direction in FIG. 18A along the ceiling surface201. Therefore, the length of the linear panel structure 311 (e.g.,311R) is appropriately adjusted according to the inserted length of thewidthwise inner end of the adjacent linear panel structure 311 (e.g.,311U or 311D). Similarly, sizes of the other linear panel structures 311and corner panel structures 312 are adjusted. In this example, however,we assume that all the linear and corner panel structures 311, 312 areof the standard width and that the widthwise inner end is not insertedinto between the air-conditioning apparatus 200 and the ceiling surface201, and therefore it is not necessary to cut any of them along thegroove.

[0207] Then, four linear panel structures 311 are mounted at theirpredetermined positions according to the widths and lengths thereof onthe ceiling 201 and then the corner panel structures 312 are mounted attheir predetermined corners to be superposed on the edges or ends 311 aof the linear panel structure 311. Upon the mounting of each linearpanel structure 311, the associated linear base member 320 isprovisionally fixed on the ceiling 201 by means of a few (e.g., about2-3) screws through the elongated holes, and then the linear covermember 340 is attached to the linear base member 320 so that a pair ofthe engaged portions thereof are engaged with a pair of the engagingportions of the linear base member 320 as described before. Further, thecorner base member 370 of the corner panel structure 312 is put on theedges of the adjacent linear panel structures 311 among the four linearpanel structures 311R, 311L, 311D, 311U and is provisionally fixed tothe ceiling surface 201 by means of fixing means such as screws. Thus,four corner base members 370 are provisionally fixed and the overall orwhole arrangement thus assembled is checked from the floor.

[0208] For example, in a case where the longitudinal position of thelinear panel structure 311 is not appropriate, corner base members 312put on the inappropriately positioned linear panel structure 311 inquestion and provisionally fixed to the ceiling surface 201 is detachedand then the linear cover member 340 of the linear panel structure 311in question is disengaged from the linear base member 320 thereof,whereupon the U-shaped portion 340 u of the linear cover member 340 ispressed toward the ceiling surface 201 to expand the leg portion 341 ofthe “U” to displace the engaged projection 361 thereof along theinclined face 336 b to be disengaged as described before. Meanwhile,because each of the linear cover and base members 340, 320 is configuredto be produced by extrusion molding, i.e., in the constant or uniformcross-sectional shape, the linear cover member 340 may be disengagedfrom the linear base member 320 by drawing or pushing the member 340 inthe longitudinal direction thereof relative to the member 320. Then, thescrews are loosened to allow the linear base member 320 to be displacedor shifted to a new provisional fixing position, and thereafter thelinear cover member 340 and corner base member 370 are superposed againto be provisionally fixed. If desired, in a condition where the cornerbase member 370 is disengaged or where some of the corner base members370 are provisionally fixed, the linear panel structure 311 asprovisionally fixed by the screws through the elongated holes may be hitwith a hammer or the like to adjust the longitudinal position ofthereof. Thus, when the width, length and mounting position of eachlinear panel structure 311 are finally determined, the linear covermembers 340 are disengaged again, and each linear base member 320 isfixed to the ceiling surface 201 at the predetermined number ofpositions by means of the screws or the like. Further, the linear covermembers 340 are engaged with the associated linear base members 320 tobe fixed thereto, thereby completing the mounting of the four linearpanel structures 311. Then, the corner base members 370 having beenadjusted to predetermined sizes if necessary are superposed on theassociated adjacent ends of the linear panel structures 311, 311 andfixed to the ceiling surface 201. Finally, the corner cover members 390are put on the four corner base members 370 to complete the corner panelstructures 312, thereby completing the assembly of the ceiling panelstructure 310. The ceiling panel structure 310 thus mounted also looksas shown in FIG. 3 when viewed in an oblique view.

[0209] In the meantime, the ceiling surface 201 on which the ceilingpanel structure 310 is to be mounted as described above is, however, notcompletely planar, i.e., not an ideal plane, but is more or lessundulated or irregular in comparison with the planar plane. In a casewhere the air-conditioning apparatus 200 is relatively large in size andhas a length of, for example, about 2 meters, the undulation orirregularity of the ceiling surface 201 may become not negligible. Inthe ceiling panel structure 310 according to a preferred embodiment ofsaid one aspect of the invention, however, because most of the parts ofthe linear base member 320 is constituted by plate-like portions, alsobecause the length or height of the projection or protrusion portions ofthe plate-like portions of the linear base member 320 in perpendicularthereto have relatively short while the width thereof is relativelynarrow, and because the projection or protrusion portions extend overthe whole length of the linear base member 320, the linear base member320 can be relatively flexible in the directions Q1, Q2 in FIG. 20.Therefore, even in a case where the ceiling surface 201 is undulated inthe longitudinal direction of the linear base member 320, the linearbase member 320 can be mounted on the ceiling surface 201 while beingdeformed along or according to the undulation of the ceiling surface201.

[0210] Then, when the linear cover member 340 is engaged with and fixedto the linear base member 320 having been undulated along thelongitudinal direction thereof, the engaged projection 357 d of thelinear cover member 340 having the inwardly tapered wedge-like distalend is fitted by force into the inwardly widely opened engaging recess331 of the linear base member 320 along the plane 328 of the guide plateportion 326 thereof, whereupon fitting of the tapered engaged projection357 into the widely opened engaging recess 331 is ensured even when thelinear base member 320 is undulated to some extent, by pushing ordrawing the engaged projection 357 d along the plane of the guide plateportion 326 of the linear base member 320. Meanwhile, because both ofthe engaged projection 357 d of the linear cover member 340 and theprojecting wall part 332 of the engaging recess 331 of the linear basemember 320 extend continuously along the longitudinal direction of themembers 340, 320, even assuming that there should be part(s) where thefitting or insertion cannot be easily performed, according to theprogress of the engagement (i.e., increase in the insertion depth of theprojection into the associated recess) at regions continuously adjacentthe not-easily-inserted part(s), the not-easily-inserted part(s) of theengaged portion 357 of the linear cover member 340 can be deformed to beundulated in the direction(s) Q1, Q2 gradually (refer to FIG. 22),thereby the fitting or inserting at the not-easily-inserted part(s) canbe started to proceed. Herein, it should be noted that the some extentof flexion or bending of the linear cover member 340 can be generatedbecause the length of projection of the engaged portion 357 of thelinear cover member 340 from the generally plate-like portions 353, 351thereof in a direction perpendicular thereto is relatively short,although the engaged portion 357 is in general not easily flexed or bentto be undulated in the longitudinal direction in comparison with thesimple plate. When the engaging recess 331 is opened to be widerwidthwise inwardly, the engaged projection 357 d need not be wedge-likeor not tapered. When the engaged projection 357 d is tapered or ofwedge-like shape, the engaging recess may be opened to have a constantwidth in the widthwise direction.

[0211] After completing the engagement of the engaged projection 357 dwith the engaging recess 331, the widthwise outer engaged projection 361of the linear cover member 340 is engaged with the widthwise outerengaging recess 334 of the linear base member 320. As for thisengagement, because there is actually an allowance or tolerance, in thevertical position of the projection 361 relative to the engaged recess334, by a height corresponding to the length of the upper inclined face336 b, some degree of undulation can be absorbed or compensated byvariation in the vertical position of the projection 361. In addition,deviation of the widthwise position of the engaged projection 361associated with the displacement or deviation in the vertical positioncan be absorbed or compensated by flexure or bending of the U-shapedportion 340 of the linear cover member 340 in the direction B1 or B2.

[0212] Thus, even in the case where the ceiling surface 201 isundulated, the engagement of the linear cover member 340 with the linearbase member 320 is ensured so that the linear cover and base members340, 320 can be assembled into the linear panel structure 311.Meanwhile, undulation of the ceiling surface 201 can be substantiallynegligible within a narrow region defined by the sizes of the cornerpanel structure 312.

[0213] The function of the ceiling panel structure 310 upon operation ofthe air-conditioning apparatus 200 is illustrated in FIG. 32 which issubstantially the same as FIG. 13 for the ceiling panel structure 10and, therefore detailed description is omitted to avoid repetition. Thedescription of the function of the ceiling panel structure 10 can beapplied to the description for the ceiling panel structure 310 of FIG.32, only if elements of the ceiling panel structure 10 in FIG. 13 suchas the guide plate portion 26, the flow-resistant projections 30, 49,the guide portion 51, the deflection guide wall portion 47 and the lowerend 43 of the linear panel structure 11 as well as the corner panelstructure 12 are substituted respectively by corresponding elements ofthe ceiling panel structure 310 such the guide plate portion 326, theflow-resistant projections 359, 349, the guide portion 351, thedeflection guide wall portion 347 and the lower end 343 of the linearpanel structure 311 as well as the corner panel structure 312.

[0214] As described before, in a case where the air-outlet is provided,for example, along two parallel sides or only along one side of thequadrilateral air-conditioning apparatus as in the one-way orunidirectional flow type or two-way or two-direction flow type ofceiling-mounted air-conditioning apparatus, the linear panel structuremay be mounted only along the side(s) adjacent and opposed to theair-outlet(s), preferably over a range longer enough than that of theair-outlet(s).

[0215] In this connection, when the linear panel structure 311 ismounted without the corner panel structure(s) 312, an end cap 450 asshown in FIGS. 33A-F is fitted on and around either end of the linearpanel structure 311. The end cap shown in FIGS. 33A-F is configured tobe fitted on one end (right end when viewed toward downstream of theairflow) of the linear panel structure 311 and the end cap for another(left) end thereof should be, as a matter of course, configured mirrorsymmetrical with respect to the end cap 450 shown in FIGS. 33A-F, thedetailed description of which is omitted herein.

[0216] The end cap 450 comprises an end wall portion 470 and projectingportions, projecting from an inner face thereof, such as projecting wallportions and projection portions, and is configured to be fitted on andaround the end portions 311 a (FIG. 19A) of the linear panel structure311. More specifically, lower wall portions 451, 452, 453, 454 of theend cap 450 are configured substantially same respectively as theassociated wall portions 374, 375 a, 376 a, 377 a of the corner basemember 320 of the corner panel structure 312. Lower wall portions 455,456, 457, 458, 459 have inner faces respectively configured to becomplementary with the outer faces of the associated wall portions 347,345, 343, 341, 333 of the linear panel structure 311. Between the wallportions 458, 459 is formed a concave wall portion 458 a, an inwardlyconvex inner face of which contacts a concave face defined by aninclined face near the distal end 341 of the linear cover member 340 ofthe linear panel structure 311 and by the inclined face 336 b of thelinear base member 320 (refer for example to FIG. 19B as to the shape orconfiguration of the linear panel structure 311). Grooves 451 g areformed, at regular intervals in an inner face of the wall portion 451,for allowing to adjust a widthwise length thereof according to thewidth-adjustment of the linear panel structure 311. An upper projections460 are engaged with the recess 327 c in the upper face of the linearpanel structure 311. Each projection 460 has an width smaller than thatof the recess 327 c and is relatively long and is tapered toward thedistal end, so that the end cap 450 can cover the end of the linearpanel structure 311 even in a case where the end is cut along adirection which deviates to some extent from the direction perpendicularto the longitudinal direction. In addition, even in a case where lengthsof the linear base member 320 and linear cover member 340 of the linearpanel structure are different to some extent from each other, thedifference can be covered by the wall portions 451-459 of the end cap450. Although the end cap 450 has three upper projections 460 in theillustrated embodiment, the number thereof may be much greater orsmaller. The end cap 450 further comprises, on the end wall 470, acylindrical projection 461 to be fitted in a recess defined by thepartially cylindrical wall portion 349 among recesses of the U-shapedportion 340 u of the linear cover member 340 of the linear panelstructure 311, a tubular projection 462 of a generally quadrilateralcross-section to be fitted in the lower recess defined by parts of thewall portions 345, 343, 341 near lower ends thereof, and a tubularprojection 463 of a generally triangular cross-section to fit in atriangle space or cavity portion defined by the wall portion 336 and themain plate portion 322 of the linear base member 320.

[0217] The end cap 450 and another end cap of mirror symmetrical theretoare fitted on and around the respective ends the linear panel structure311, after the linear panel structure 311 has been mounted on theceiling surface at the predetermined position and after the end capshave been adjusted in size to be adapted to the width of the linearpanel structure 311, thereby completing to form the linear panelstructure apparatus. The lower wall portion 451 of the end cap 450 iscut out at a distal end 451 a thereof and, therefore, a narrow part ofthe end wall portion 470 situated more upstream than the distal end 451a can be inserted into between the ceiling surface 201 and the outerframe such as smoothly planed board of the air-conditioning apparatus200. In a case where the projection 327 e (imaginary line in FIG. 20) isformed on the surface 328 of the linear base member 320 of the linearpanel structure 311, the cut-out end 451 a abuts against the downstreamface of the projection 327 e. If desired for regulating or suppressingairflow flowing over the end cap 450 in the longitudinal direction ofthe linear panel structure 311, the wall portions 451-456 may be curved,similarly to the corner base member 370, to be situated more upstream asapproaching closer to the end wall portion 470.

[0218] The description of the preferred embodiments heretofore have beenmade based on an assumption that the ceiling panel structure 310, i.e.,structure 311 and/or 312, is mounted or installed on the ceiling surface201 at the downstream of the air-outlet 211 of the ceiling mountedair-conditioning apparatus having the room air-inlet 210 at the centralportion thereof and the conditioning air-outlet at the peripheralportion thereof. However, the features of the ceiling panel structure310, i.e., structure 311 and/or 312, is also all effective, except for apart of the conditioning air is return to the air-inlet 210, even in acase where the structure is mounted or installed on or embedded in theceiling surface 201 at the downstream of the conditioning air-outlet 211of an conditioning air discharge or blowout apparatus having only theair-outlet 211, i.e., having no air-inlet at the ceiling surface 201,instead of the ceiling-mounted air-conditioning apparatus 200.Therefore, the ceiling panel structures, such as those illustrated inthe drawings hereinbefore, according to the embodiments of the inventioncan be applied also to the ceiling-mounted or embedded type ofconditioning air discharge apparatus, such as the air-conditioning duct,having an air-outlet with an aperture at the ceiling surface, in whichthe whole region of the aperture serves as the air-outlet or airdischarge aperture but not as the air-inlet, so as to minimize oreliminate the smudging or contamination of the ceiling surface 201around the apparatus. A typical conditioning air discharge apparatusincludes, for example, one having plural coaxial and circular or annulardischarge apertures between adjacent hollow frust-conical dischargepassage-defining walls known as “anemometer” as shown in FIG. 1G. Forthe apparatus having a circular outer circumference, a further guideplate may be added to cover a ceiling surface between the circularconditioning-air-discharge apparatus and the inner edge of thequadrilateral or square ceiling panel structure, if desired.

What is claimed is:
 1. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a conditioning air-outlet of a ceiling-mounted air-conditioning apparatus, having a room air-inlet at a central portion thereof and the air-outlet at a peripheral portion thereof, said ceiling panel structure being adapted to be mounted to the ceiling at an outside of the air-conditioning apparatus, and comprising a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the outlet of the air-conditioning apparatus, back to the room air-inlet.
 2. A ceiling panel structure according to claim 1 , comprising: at least one base member adapted to be mounted to a ceiling at the downstream of the air-conditioning apparatus and having an engaging portion at a side opposite to a side faced to the ceiling; and at least one cover member engaged at an engaged portion thereof with the engaging portion of said at least one base member to be fixed thereto, said at least one cover member having the deflection induction portion.
 3. A ceiling panel structure according to claim 2 , wherein said at least one base member comprises a linear base member capable of being mounted at one principal face thereof to a surface of the ceiling to extend along at least one linear side edge of the air-conditioning apparatus, the linear base member having an adjustable length and/or width, and said at least one cover member comprises a linear cover member engaged with the linear base member and having an adjustable length.
 4. A ceiling panel structure according to claim 3 , wherein the linear base member comprises, a conditioning airflow guide surface at one widthwise end portion of a principal face opposite to said one principal face generally parallel to said one principal face, said one widthwise end portion being closer, than another widthwise end, to the side edge of the air-conditioning apparatus where the air-outlet is provided; and the engaging portion at a position more remote, than the guide surface, in the widthwise direction from the side edge of the air-conditioning apparatus, and wherein the linear cover member comprises the deflection induction portion for deflecting a part of the conditioning air, flowing along the guide surface of the linear base member, back to the room air-inlet.
 5. A ceiling panel structure according to claim 4 , wherein the linear base member further comprises a flow-resistant projection portion, at a widthwise outer end of the guide surface, engaged with a widthwise inner end of the linear cover member and serving as a resistance against the airflow for reducing a flow rate of the conditioning air having spread along the guide surface.
 6. A ceiling panel structure according to claim 3 , wherein the base member includes a corner base member capable of being mounted at one principal face thereof to the ceiling surface adjacent to a longitudinal end of the linear base member at an outside of a corner portion of the air-conditioning apparatus, and wherein the cover member includes a corner cover member engaged with the corner base member adjacent to a longitudinal end of the linear cover member.
 7. A ceiling panel structure according to claim 2 , wherein the base member includes a corner base member capable of being mounted to a surface of the ceiling at an outside of a corner portion of the air-conditioning apparatus, and wherein the cover member includes a linear cover member engaged with the corner base member at either longitudinal end thereof and having an adjustable length and width; and a corner cover member engaged with the corner base member adjacent to the longitudinal end of the linear cover member.
 8. A ceiling panel structure according to claim 2 , wherein the cover member comprises a flow-resistant projection portion, at an upstream of the deflection induction portion, which serves as a resistance against the airflow for reducing a flow rate of the conditioning air flowing along the surface of the cover member.
 9. A ceiling panel structure according to claim 2 , wherein each of the base and cover members is made of plastic material.
 10. A ceiling panel structure according to claim 2 , wherein each of the base and cover members are made of substantially opaque material.
 11. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a conditioning air-outlet of a ceiling-mounted air-conditioning apparatus, having a room air-inlet at a central portion thereof and the air-outlet at a peripheral portion thereof, said ceiling panel structure comprising linear panel structures and corner panel structures, wherein each of the linear panel structures comprises a base member capable of being mounted to a surface of the ceiling at one principal face thereof to extend along an associated linear side edge of the air-conditioning apparatus, a length and width of the base member in an extending direction thereof being adjustable, the base member having an engaging portion at a principal face thereof opposite to said one principal face, a cover member of an adjustable length and width adapted to be engaged with the engaging portion of the associated base member at an engaged portion thereof to be fixed thereto, the cover member having a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the outlet of the air-conditioning apparatus, back to the room air-inlet, and each of the corner panel structure is adapted to be positioned between adjacent ends of the associated linear panel structures to be engaged with the adjacent ends.
 12. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a conditioning air-outlet of a ceiling-mounted air-conditioning apparatus, having a room air-inlet at a central portion thereof and the air-outlet at a peripheral portion thereof, the ceiling panel structure including a deflection induction portion which is substantially rigid against an airflow to deflect the conditioning air, having been blown out through the outlet of the air-conditioning apparatus, in a direction away from the ceiling, the ceiling panel structure comprising a base structure adapted to be mounted to a ceiling at an outside of the air-conditioning apparatus and having an engaging portion at a side opposite to a side faced to the ceiling, the base structure including a linear base member adapted to be mounted to a surface of the ceiling at one principal face thereof to extend along a side edge of the air-conditioning apparatus; and a cover structure engaged at an engaged portion thereof with the engaging portion of the base structure to be fixed thereto, the cover structure including a linear cover member adapted to be engaged with the linear base member and having the deflection induction portion; wherein the engaging portion of the linear base member comprises a pair of engaging recesses spaced from each other in a widthwise direction thereof and opened at opposite sides to be faced away from each other, one of the recesses having side walls, one of the side walls situated closer to the surface of the ceiling than another of the side walls having an inclined face inclined to be closer to the surface of the ceiling as departing more remote from another of the recesses, and wherein the engaged portion of the linear cover member comprises a pair of engaged projections, to be engaged with the pair of engaging recesses of the linear base member, at regions spaced from each other in a widthwise direction of the linear cover member, the pair of the engaged projections being situated at sides faced to each other and being capable of being displaced resiliently toward/from each other, one of the projections having a guide part movable along the inclined face of the side wall, closer to the surface of the ceiling, of said one recess.
 13. A ceiling panel structure according to claim 12 , wherein the linear cover member has a generally U-shaped cross-section, one engaged projection, of said one pair of the engaged projections, engaged with said one recess of the linear base member is formed at one of two legs of the “U”, and the deflection induction portion is formed at another of the two legs.
 14. A ceiling panel structure according to claim 13 , wherein said another side wall situated more remote from the ceiling surface than said one side wall having an inclined face, at a side opposite to a side faced to the ceiling surface, inclined to be closer to the ceiling surface as departing more remote from said another recess.
 15. A ceiling panel structure according to claim 12 , wherein each of said one pair of recesses of the linear base member extend continuously along an extending direction thereof over a substantially whole length thereof.
 16. A ceiling panel structure according to claim 12 , wherein said one recess of said one pair of recesses is more remote than said another recess from the air-outlet of the air-conditioning apparatus.
 17. A ceiling panel structure according to claim 16 , wherein the linear base member comprises a conditioning airflow guide face at a widthwise end portion, adjacent to the side edge of the air-conditioning apparatus where the air-outlet is provided, of a principal face opposite to said one principal face generally parallel to said one principal face; and said another engaging portion at a position more remote in the widthwise direction than the guide face from the edge of the air-conditioning apparatus, and wherein the linear cover member comprises said another engaged portion, engaged with said another engaging portion of the linear base member, at a widthwise inner end thereof, a part of said another engaged portion faced to the air-outlet of the air-conditioning apparatus serves as a flow-resistant projection acting as a resistance against the airflow for reducing a flow rate of the conditioning airflow having flown along the guide face of the linear base member.
 18. A ceiling panel structure according to claim 17 , wherein the linear cover member comprises a plate portion, extending generally parallel with the ceiling surface, adjacent to said another engaged portion thereof.
 19. A ceiling panel structure according to claim 12 , wherein the linear base member and the linear cover member are configured to be formed by extrusion molding of plastic material.
 20. A ceiling panel structure according to claim 12 , wherein the linear base member of the linear panel structure has an adjustable length and/or width and the linear cover member of the linear panel structure has an adjustable length.
 21. A ceiling panel structure according to claim 12 , wherein the base structure comprises a corner base member capable of being mounted to the ceiling surface at one principal face thereof adjacent to a longitudinal end of the linear base member to be positioned at an outside of a corner portion of the air-conditioning apparatus, and wherein the cover structure comprises a corner cover member engaged with the corner base member adjacent to the longitudinal end of the linear cover member.
 22. A ceiling panel structure according to claim 21 , wherein the corner base member is adapted, for the engagement, to be positioned over associated ends of the linear base and cover members.
 23. A ceiling panel structure according to claim 21 , wherein the corner cover member comprises a part of the deflection induction portion which is substantially rigid against the airflow to deflect a part of the conditioning air, having been blown out through the air-outlet of the air-conditioning apparatus, in a direction away from the ceiling surface, and wherein the corner cover member has a generally U-shaped cross-section, the corner cover member being engaged with an outwardly engaging portion of an outer side wall of the corner base member at an inwardly engaged portion of one of two leg parts of the “U”, and contacting at an inner face of a bottom part of the “U” with an extending end of the deflection induction portion of the corner base member.
 24. A ceiling panel structure according to claim 23 , wherein the corner base member comprises a deflection induction portion serving as a flow-resistant projection acting as a resistance against the airflow for reducing a flow rate of the conditioning airflow having flown along the surface of the corner base member.
 25. A ceiling panel structure according to claim 12 , further comprising an end cap to fitted over at least one of longitudinal ends of linear base and cover structures in a state where the engaging portion of the linear base member and the engaged portion of the linear cover member are engaged with each other.
 26. A ceiling panel structure according to claim 12 , wherein the linear base member and the linear cover member are made of substantially opaque material.
 27. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a conditioning air-outlet of a ceiling-mounted air-conditioning apparatus, having a room air-inlet at a central portion thereof and the air-outlet at a peripheral portion thereof, the ceiling panel structure including a deflection induction portion which is substantially rigid against an airflow to deflect the conditioning air, having been blown out through the outlet of the air-conditioning apparatus, in a direction away from the ceiling, the ceiling panel structure comprising linear panel structures; and corner panel structures positioned between adjacent ends of the linear panel structures and engaged thereto, each linear panel structure comprising a base member capable of being mounted to a surface of the ceiling at one principal face thereof to extend along an associated linear side edge of the air-conditioning apparatus and having an adjustable length and width in the extending direction, the base member having an engaging portion at a principal face opposite to said one principal face, and a cover member of an adjustable length and width adapted to be engaged with the engaging portion of the associated base member at an engaged portion thereof to be fixed thereto, the cover member having a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the air-outlet of the air-conditioning apparatus, in a direction away from the ceiling, wherein the engaging portion of the linear base member comprises a pair of engaging recesses spaced and faced away from each other in a widthwise direction of the linear base member, the pair of engaging recess portions extending in an extending direction of the linear base member, one of a pair of engaging recesses having side walls, one of the side walls closer to a surface of the ceiling than another of the side walls having an inclined face inclined to be closer to the ceiling surface as departing more remote from another of the pair of recesses, and wherein the engaged portion of the linear cover member comprising a pair of engaged projections, engaged with the pair of engaging recesses of the linear base member, spaced from and faced to each other in a widthwise direction of the linear cover member, one of the projections having a guide part movable along the inclined face of the side wall, closer to the ceiling surface, of said one recess.
 28. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a periphery of a conditioning air-outlet of a ceiling-mounted conditioning-air-discharge apparatus, having the air-outlet at a surface of the ceiling, said ceiling panel structure comprising: at least one base member adapted to be mounted to the ceiling at the downstream of the air-discharge apparatus and having an engaging portion at a side opposite to a side faced to the ceiling; and at least one cover member engaged at an engaged portion thereof with the engaging portion of said at least one base member to be fixed thereto, said at least one cover member having a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the outlet of the air-discharge apparatus, in a direction away from the ceiling.
 29. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a periphery of a conditioning air-outlet of a ceiling-mounted conditioning-air-discharge apparatus, having the air-outlet at a surface of the ceiling, said ceiling panel structure comprising linear panel structures and corner panel structures, wherein each of the linear panel structures comprises a base member capable of being mounted to a surface of the ceiling at one principal face thereof to extend along an associated linear side edge of the air-discharge apparatus, a length and width of the base member in an extending direction thereof being adjustable, the base member having an engaging portion at a principal face thereof opposite to said one principal face, a cover member of an adjustable length and width adapted to be engaged with the engaging portion of the associated base member at an engaged portion thereof to be fixed thereto, the cover member having a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the outlet of the air-discharge apparatus, in a direction away from the ceiling, and each of the corner panel structure is adapted to be positioned between adjacent ends of the associated linear panel structures to be engaged with the adjacent ends.
 30. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a periphery of a conditioning air-outlet of a ceiling-mounted conditioning-air-discharge apparatus, having the air-outlet at a surface of the ceiling, the ceiling panel structure including a deflection induction portion which is substantially rigid against an airflow to deflect the conditioning air, having been blown out through the outlet of the conditioning-air-discharge apparatus, in a direction away from the ceiling, the ceiling panel structure comprising a base structure adapted to be mounted to a ceiling at an outside of the air-discharge apparatus and having an engaging portion at a side opposite to a side faced to the ceiling, the base structure including a linear base member adapted to be mounted to a surface of the ceiling at one principal face thereof to extend along a side edge of the air-discharge apparatus; and a cover structure engaged at an engaged portion thereof with the engaging portion of the base structure to be fixed thereto, the cover structure including a linear cover member adapted to be engaged with the linear base member and having the deflection induction portion; wherein the engaging portion of the linear base member comprises a pair of engaging recesses spaced from each other in a widthwise direction thereof and opened at opposite sides to be faced away from each other, one of the recesses having side walls, one of the side walls situated closer to the surface of the ceiling than another of the side walls having an inclined face inclined to be closer to the surface of the ceiling as departing more remote from another of the recesses, and wherein the engaged portion of the linear cover member comprises a pair of engaged projections, to be engaged with the pair of engaging recesses of the linear base member, at regions spaced from each other in a widthwise direction of the linear cover member, the pair of the engaged projections being situated at sides faced to each other and being capable of being displaced resiliently toward/from each other, one of the projections having a guide part movable along the inclined face of the side wall, closer to the surface of the ceiling, of said one recess.
 31. A ceiling panel structure adapted to be mounted to a ceiling at a downstream of a periphery of a conditioning air-outlet of a ceiling-mounted conditioning-air-discharge apparatus, having the air-outlet at a surface of the ceiling, the ceiling panel structure including a deflection induction portion which is substantially rigid against an airflow to deflect the conditioning air, having been blown out through the outlet of the conditioning air-discharge apparatus, in a direction away from the ceiling, the ceiling panel structure comprising linear panel structures; and corner panel structures positioned between adjacent ends of the linear panel structures and engaged thereto, each linear panel structure comprising a base member capable of being mounted to a surface of the ceiling at one principal face thereof to extend along an associated linear side edge of the air-discharge apparatus and having an adjustable length and width in the extending direction, the base member having an engaging portion at a principal face opposite to said one principal face, and a cover member of an adjustable length and width adapted to be engaged with the engaging portion of the associated base member at an engaged portion thereof to be fixed thereto, the cover member having a deflection induction portion which is substantially rigid against an airflow to deflect a part of the conditioning air, having been blown out through the air-outlet of the air-conditioning apparatus, in a direction away from the ceiling, wherein the engaging portion of the linear base member comprises a pair of engaging recesses spaced and faced away from each other in a widthwise direction of the linear base member, the pair of engaging recess portions extending in an extending direction of the linear base member, one of a pair of engaging recesses having side walls, one of the side walls closer to a surface of the ceiling than another of the side walls having an inclined face inclined to be closer to the ceiling surface as departing more remote from another of the pair of recesses, and wherein the engaged portion of the linear cover member comprising a pair of engaged projections, engaged with the pair of engaging recesses of the linear base member, spaced from and faced to each other in a widthwise direction of the linear cover member, one of the projections having a guide part movable along the inclined face of the side wall, closer to the ceiling surface, of said one recess. 